Manufacturing method of wiring board

Abstract

To provide a manufacturing method for a wiring board that has excellent recess formability and minimize step differences in a cross-sectional shape.SOLUTION: A manufacturing method for a wiring board includes a step (A) of forming, in this order, an insulating layer (20) containing a cured product of a resin composition and a thermoplastic resin layer (30) on a substrate (10), a step (B) of forming a mask pattern (40') on the thermoplastic resin layer, and a step (C) of performing wet blasting treatment using abrasive grains to form recesses in the thermoplastic resin layer and the insulating layer, and the resin composition contains a thermosetting resin.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a wiring board. [Background technology]

[0002] In recent years, there has been an increasing need for substrates that require high-frequency characteristics by using insulating materials with excellent electrical properties, such as modified polyimides or liquid crystal polymers. Laminating modified polyimides or liquid crystal polymers requires high-temperature processing. Therefore, it is common to use a thermosetting resin as a bonding sheet, forming a two-layer structure consisting of the bonding sheet and an insulating material with excellent electrical properties, such as modified polyimides or liquid crystal polymers. Many such bonding sheets have been developed, including the resin compositions described in Patent Document 1, for example. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-59779 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, in order to improve the electrical properties of printed wiring boards and wiring boards such as semiconductor package substrates in which semiconductor chips are bonded to printed wiring boards, layers of modified polyimides or liquid crystal polymers have been laminated onto substrates. Laminating such layers as a single layer generally requires processing under high-temperature conditions. Therefore, lamination is often performed using an insulating layer that functions as a bonding sheet. A bonding sheet is an adhesive sheet that is placed between each layer of a multilayer structure to bond the layers together and also functions as an insulating layer to insulate the layers from each other.

[0005] When manufacturing a wiring board, a via hole or a trench may be formed in an insulating layer and a layer such as a modified polyimide. A "via hole" usually refers to a hole that penetrates the insulating layer and a layer such as a modified polyimide. A "trench" refers to a depression that does not penetrate the insulating layer and is generally formed in a groove shape. Hereinafter, via holes and trenches may be collectively referred to as "recesses." A method using a laser is considered as a method for forming recesses.

[0006] The present inventors have found that laser irradiation generates heat, which can cause interfacial peeling between the insulating layer and the layer of modified polyimide or the like, and that the subsequent desmearing treatment can further erode the resin around the recesses in the insulating layer because the degree of roughening of the surface of each layer varies depending on the components contained in each layer, resulting in steps in the cross-sectional shape of the recesses near the interface between the insulating layer and the layer of modified polyimide or the like. If such steps are large, there can be areas in which a conductor layer is not formed, particularly in via holes, which can reduce the reliability of the electrical connection.

[0007] The present invention has been made in view of the above circumstances, and aims to provide a method for manufacturing a wiring board that is excellent in the formability of recesses and that suppresses step differences in the cross-sectional shape. [Means for solving the problem]

[0008] As a result of intensive research to solve the above-mentioned problems, the inventors discovered that forming recesses by wet blasting treatment results in excellent recess formability and suppresses steps in the cross-sectional shape, and thus completed the present invention.

[0009] That is, the present invention includes the following. [1] (A) forming an insulating layer containing a cured product of a resin composition and a thermoplastic resin layer in this order on a substrate; (B) forming a mask pattern on the thermoplastic resin layer; and (C) A method for manufacturing a wiring board, comprising a step of performing a wet blasting process using abrasive grains to form recesses in the thermoplastic resin layer and the insulating layer. [2] The method for producing a wiring board according to [1], wherein the resin composition contains a thermosetting resin. [3] The method for manufacturing a wiring board according to [2], wherein the thermosetting resin includes an epoxy resin. [4] The method for manufacturing a wiring board according to [2] or [3], wherein the thermosetting resin contains a curing agent. [5] The method for producing a wiring board according to [4], wherein the curing agent includes an active ester curing agent. [6] The method for producing a wiring board according to any one of [1] to [5], wherein the resin composition contains an inorganic filler. [7] The method for producing a wiring board according to [6], wherein the inorganic filler contains silica or alumina. [8] The method for producing a wiring board according to [6] or [7], wherein the content of the inorganic filler is 20% by mass or more when the non-volatile components of the resin composition are 100% by mass. [9] The method for producing a wiring board according to any one of [1] to [8], wherein the thermoplastic resin layer contains polyimide.

[10] The method for manufacturing a wiring board according to any one of [1] to [9], wherein b / c is 0.5 or more and 10 or less, where b is the thickness of the thermoplastic resin layer and c is the thickness of the insulating layer.

[11] The method for producing a wiring board according to any one of [1] to

[10] , wherein the insulating layer has a tensile modulus of elasticity of 1 GPa or more.

[12] The method for producing a wiring board according to any one of [1] to

[11] , wherein the thickness of the mask pattern is 1 μm or more.

[13] The method for manufacturing a wiring board according to any one of [1] to

[12] , wherein the mask pattern is a metal mask pattern.

[14] The method for manufacturing a wiring board according to

[13] , wherein the metal mask pattern contains copper.

[15] The method for producing a wiring board according to any one of [1] to

[14] , wherein the wiring board is a semiconductor package substrate.

[16] The method for producing a wiring board according to any one of [1] to

[15] , wherein the wiring board is used in a semiconductor device. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a method for manufacturing a wiring board that is excellent in the formability of recesses and that suppresses step differences in the cross-sectional shape. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of a state in which a thermoplastic resin layer is laminated on a resin composition layer. [Figure 2] FIG. 2 is a cross-sectional view schematically showing an example of the state after step (B-1) has been performed. [Figure 3] FIG. 3 is a cross-sectional view schematically showing an example of a state in which a photosensitive layer is formed on a metal layer. [Figure 4] FIG. 4 is a cross-sectional view schematically showing an example of the state after the photosensitive layer has been patterned. [Figure 5] FIG. 5 is a cross-sectional view schematically showing an example of the state after step (B-3) has been performed. [Figure 6] FIG. 6 is a cross-sectional view schematically showing an example of the state after step (B-4) has been performed. [Figure 7] FIG. 7 is a cross-sectional view schematically showing an example of a state after the mask pattern is removed after the via holes are formed. [Figure 8] FIG. 8 is a cross-sectional view schematically showing an example of the state after step (C) has been performed. [Figure 9] FIG. 9 is a cross-sectional view schematically showing an example of the state after step (Ba) is performed. [Figure 10] FIG. 10 is a cross-sectional view schematically showing an example of the state after step (Bb) is performed. [Figure 11] FIG. 11 is a cross-sectional view schematically showing an example of the state after step (Bc) has been performed. [Figure 12] FIG. 12 is a cross-sectional view schematically showing an example of the state after step (Bd) has been performed. [Figure 13] FIG. 13 is a cross-sectional view schematically showing an example of the state after the step (Be) is performed. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples described below, and can be implemented with any modifications within the scope of the claims of the present invention and their equivalents.

[0013] Before describing the method for producing a wiring board of the present invention, a resin composition used to form the insulating layer of the wiring board and a resin sheet used in producing the wiring board will be described.

[0014] [Resin composition] The cured product of the resin composition used to form the insulating layer can function not only as an insulating layer but also as a bonding sheet that bonds the substrate and the thermoplastic resin layer. Therefore, the resin composition is used as a bonding sheet, and it is preferable that the cured product has sufficient insulating properties. For example, conventional components used in forming insulating layers of wiring boards can be used as such resin compositions, specifically compositions containing a thermosetting resin. Therefore, in one embodiment, the resin composition contains (a) a thermosetting resin. The resin composition may further contain additives such as (b) an inorganic filler, (c) a thermoplastic resin, (d) a curing accelerator, (e) other additives, and (f) a solvent, as needed.

[0015] -(a) Thermosetting resin- The resin composition contains a thermosetting resin (a) as component (a). The type of thermosetting resin (a) is not particularly limited as long as it can be cured by heat. One type of thermosetting resin (a) may be used alone, or two or more types may be used in combination.

[0016] (a) Examples of thermosetting resins include epoxy resins, radical polymerizable resins, phenolic resins, cyanate resins, active ester resins, carbodiimide resins, acid anhydride resins, amine resins, benzoxazine resins, and thiol resins.

[0017] The (a) thermosetting resin is preferably a combination of an epoxy resin and a resin capable of reacting with the epoxy resin to cure the resin composition. Hereinafter, a resin capable of reacting with an epoxy resin to cure the resin composition may be referred to as a "curing agent." Therefore, the (a) thermosetting resin preferably contains an epoxy resin and a curing agent. Examples of curing agents include phenolic resins, cyanate resins, active ester resins, carbodiimide resins, acid anhydride resins, amine resins, benzoxazine resins, and thiol resins. The curing agent preferably contains an active ester resin. One type of curing agent may be used alone, or two or more types may be used in combination. In one embodiment, the (a) thermosetting resin contains an epoxy resin and an active ester resin.

[0018] The epoxy resin as component (a) is a thermosetting resin having an epoxy group. Examples of epoxy resins include bixylenol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, bisphenol AF-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol novolac-type epoxy resins, phenol novolac-type epoxy resins, tert-butyl-catechol-type epoxy resins, naphthalene-type epoxy resins, naphthol-type epoxy resins, anthracene-type epoxy resins, glycidylamine-type epoxy resins, glycidyl ester-type epoxy resins, glycidylcyclohexane-type epoxy resins, alkyl diglycidyl ether-type epoxy resins, cresol novolac-type epoxy resins, biphenyl-type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane-type epoxy resins, cyclohexane dimethanol-type epoxy resins, naphthylene ether-type epoxy resins, trimethylol-type epoxy resins, tetraphenylethane-type epoxy resins, and phenolphthalimidine-type epoxy resins. Among these, epoxy resins having an aromatic ring are preferred.

[0019] The (a) thermosetting resin preferably contains an epoxy resin having two or more epoxy groups per molecule as the epoxy resin. The proportion of the epoxy resin having two or more epoxy groups per molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more, relative to 100% by mass of the non-volatile components of the epoxy resin.

[0020] Epoxy resins include epoxy resins that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 20°C (hereinafter sometimes referred to as "solid epoxy resins"). The resin composition may contain, as component (a), only a liquid epoxy resin, only a solid epoxy resin, or a combination of a liquid epoxy resin and a solid epoxy resin. Of these, from the viewpoint of significantly achieving the effects of the present invention, it is preferable to contain a combination of a liquid epoxy resin and a solid epoxy resin.

[0021] The liquid epoxy resin is preferably a liquid epoxy resin having two or more epoxy groups in one molecule.

[0022] Preferred liquid epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, glycidyl amine type epoxy resins, and epoxy resins having a butadiene structure, glycidyl cyclohexane type epoxy resins, phenolphthalimidine type epoxy resins, and alkyl diglycidyl ether type epoxy resins, with glycidyl cyclohexane type epoxy resins being more preferred.

[0023] Specific examples of liquid epoxy resins include "HP4032", "HP4032D", and "HP4032SS" (naphthalene type epoxy resins) manufactured by DIC Corporation; "828US", "jER828EL", "825", and "Epikote 828EL" (bisphenol A type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "jER807" and "1750" (bisphenol F type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "jER152" (phenol novolac type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "630" and "630LSD" (glycidyl amine type epoxy resins) manufactured by Mitsubishi Chemical Corporation; and "ZX1" manufactured by Nippon Steel Chemical & Material Co., Ltd. Examples of epoxy resins that can be used include "EX-721" (a glycidyl ester epoxy resin) manufactured by Nagase ChemteX Corporation, "Celloxide 2021P" (an alicyclic epoxy resin having an ester skeleton) manufactured by Daicel Corporation, "PB-3600" (an epoxy resin having a butadiene structure) manufactured by Daicel Corporation, "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane epoxy resins) manufactured by Nippon Steel Chemical & Material Co., Ltd., and "YED216D" (an alkyl diglycidyl ether epoxy resin) manufactured by Mitsubishi Chemical Corporation. These may be used alone or in combination of two or more.

[0024] As the solid epoxy resin, a solid epoxy resin having two or more epoxy groups in one molecule is preferred, a solid epoxy resin having three or more epoxy groups in one molecule is more preferred, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is even more preferred.

[0025] Preferred solid epoxy resins include bixylenol-type epoxy resins, naphthalene-type epoxy resins, naphthalene-type tetrafunctional epoxy resins, cresol novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, bisphenol AF-type epoxy resins, and tetraphenylethane-type epoxy resins, with naphthalene-type epoxy resins and biphenyl-type epoxy resins being more preferred.

[0026] Specific examples of solid epoxy resins include "HP4032H" (naphthalene type epoxy resin), "HP-4700", "HP-4710" (naphthalene type tetrafunctional epoxy resin), "N-690" (cresol novolac type epoxy resin), "N-695" (cresol novolac type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" (dicyclopentadiene type epoxy resin), "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000", "HP6000L" (naphthylene ether type epoxy resin), manufactured by DIC Corporation; "EPPN-502H" (trisphenol type epoxy resin), "NC7000L" (naphthol novolac type epoxy resin), "NC3000H", "NC3000", "NC3000L" manufactured by Nippon Kayaku Co., Ltd.; Examples include "NC3100" (biphenyl-type epoxy resin); "ESN475V" (naphthalene-type epoxy resin) and "ESN485" (naphthol novolac-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YL6121" (biphenyl-type epoxy resin), "YX4000HK" (bixylenol-type epoxy resin), and "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "PG-100" and "CG-500" manufactured by Osaka Gas Chemical Co., Ltd.; "YL7760" (bisphenol AF-type epoxy resin), "YL7800" (fluorene-type epoxy resin), "jER1010" (solid bisphenol A-type epoxy resin), and "jER1031S" (tetraphenylethane-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; and "WHR-991S" (phenolphthalimidine-type epoxy resin) manufactured by Nippon Kayaku Co., Ltd. These may be used alone or in combination of two or more.

[0027] When a liquid epoxy resin and a solid epoxy resin are used in combination as the epoxy resin, the ratio by mass between them (liquid epoxy resin:solid epoxy resin) is preferably 1:0.1 to 1:20, more preferably 1:0.15 to 1:10, and particularly preferably 1:0.2 to 1:5. When the ratio by mass between the liquid epoxy resin and the solid epoxy resin is within this range, the desired effects of the present invention can be significantly achieved.

[0028] The epoxy equivalent of the epoxy resin is preferably 50 g / eq to 5000 g / eq, more preferably 50 g / eq to 3000 g / eq, even more preferably 80 g / eq to 2000 g / eq, and even more preferably 110 g / eq to 1000 g / eq. The epoxy equivalent is the mass of an epoxy resin containing one equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

[0029] The weight average molecular weight (Mw) of the epoxy resin is preferably 100 to 5000, more preferably 150 to 3000, and even more preferably 200 to 1500. The weight average molecular weight of the epoxy resin is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

[0030] The content of the epoxy resin as component (a) is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on 100% by mass of the nonvolatile components in the resin composition, and the upper limit is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less.

[0031] The content of the epoxy resin as component (a), when the resin component in the resin composition is taken as 100% by mass, is preferably 25% by mass or more, more preferably 30% by mass or more, and even more preferably 35% by mass or more, and the upper limit is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less.

[0032] In the present invention, unless otherwise specified, the content of each component in the resin composition is a value when the nonvolatile components in the resin composition are 100 mass %, and the nonvolatile components refer to all nonvolatile components in the resin composition excluding the solvent. Furthermore, the resin components in the resin composition refer to the nonvolatile components in the resin composition excluding (c) the inorganic filler.

[0033] The radical polymerizable resin as component (a) is not particularly limited in type, as long as it has one or more (preferably two or more) radical polymerizable unsaturated groups in one molecule. Examples of the radical polymerizable resin include resins having one or more radical polymerizable unsaturated groups selected from the group consisting of maleimide, vinyl, allyl, styryl, vinylphenyl, acryloyl, methacryloyl, fumaroyl, and maleoyl groups.

[0034] The type of maleimide resin is not particularly limited as long as it has one or more (preferably two or more) maleimide groups (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl groups) in one molecule. Examples of maleimide resins include: (1) maleimide resins containing an aliphatic skeleton (preferably an aliphatic skeleton having 36 carbon atoms derived from dimer diamine), such as "BMI-3000J," "BMI-5000," "BMI-1400," "BMI-1500," "BMI-1700," and "BMI-689" (all manufactured by DigiCner Molecules), and "SLK6895-T90" (manufactured by Shin-Etsu Chemical Co., Ltd.); (2) maleimide resins containing an indane skeleton, as described in the Japan Institute of Invention and Innovation Disclosure Technical Bulletin No. 2020-500211; and (3) maleimide resins containing an aromatic ring skeleton directly bonded to the nitrogen atom of the maleimide group, such as "MIR-3000-70MT" (manufactured by Nippon Kayaku Co., Ltd.), "BMI-4000" (manufactured by Daiwa Kasei Co., Ltd.), and "BMI-80" (manufactured by Keiai Kasei Co., Ltd.).

[0035] The (meth)acrylic resin may be a monomer or an oligomer, and may be any type of (meth)acrylic resin, as long as it has one or more (preferably two or more) (meth)acryloyl groups in one molecule. Here, the term "(meth)acryloyl group" is a general term for acryloyl groups and methacryloyl groups. Examples of methacrylic resins include (meth)acrylate monomers, as well as (meth)acrylic resins such as "A-DOG" (manufactured by Shin-Nakamura Chemical Co., Ltd.), "DCP-A" (manufactured by Kyoeisha Chemical Co., Ltd.), "NPDGA," "FM-400," "R-687," "THE-330," "PET-30," and "DPHA" (all manufactured by Nippon Kayaku Co., Ltd.).

[0036] (a) The content of the radical polymerizable resin as the thermosetting resin is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 1.5% by mass or more, when the non-volatile components in the resin composition layer are taken as 100% by mass, and is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

[0037] (a) The content of the radical polymerizable resin as the thermosetting resin is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, and is preferably 15% by mass or less, more preferably 12% by mass or less, and even more preferably 10% by mass or less, when the resin component in the resin composition layer is taken as 100% by mass.

[0038] The phenolic resin may be a compound having one or more, preferably two or more, hydroxyl groups bonded to an aromatic ring such as a benzene ring or a naphthalene ring per molecule. When combined with an epoxy resin, the phenolic resin may react with the epoxy resin to harden the resin composition layer, and is therefore sometimes referred to as a "phenolic curing agent." From the viewpoint of achieving the remarkable effects of the present invention, the phenolic resin is preferably a phenolic resin having a novolac structure. Furthermore, from the viewpoint of adhesion, nitrogen-containing phenolic resins are preferred, and triazine skeleton-containing phenolic resins are more preferred. Of these, triazine skeleton-containing phenolic novolac resins are preferred from the viewpoint of achieving the remarkable effects of the present invention. Specific examples of phenolic resins include "MEH-7700," "MEH-7810," and "MEH-7851" manufactured by Meiwa Chemical Industry Co., Ltd.; "NHN," "CBN," and "GPH" manufactured by Nippon Kayaku Co., Ltd.; "SN-170," "SN-180," "SN-190," "SN-475," "SN-485," "SN-495," "SN-375," and "SN-395" manufactured by Nippon Steel Chemical & Material Co., Ltd.; and "LA-7052," "LA-7054," "LA-3018," "LA-3018-50P," "LA-1356," "TD2090," "TD-2090-60M," and "KA-1163" manufactured by DIC Corporation.

[0039] As the active ester resin, compounds having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are generally preferred. When combined with an epoxy resin, active ester resins can react with the epoxy resin to cure the resin composition layer, and are therefore sometimes referred to as "active ester curing agents." The active ester resin is preferably one obtained by the condensation reaction of a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxy compound and / or a thiol compound. In particular, from the viewpoint of improving resistance to high-temperature reflow blistering, active ester resins obtained from a carboxylic acid compound and a hydroxy compound are preferred, and active ester resins obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound are more preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalene, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, and phenol novolak. Here, "dicyclopentadiene-type diphenol compounds" refers to diphenol compounds obtained by condensing one dicyclopentadiene molecule with two phenol molecules.

[0040] Specifically, the active ester resin is preferably a dicyclopentadiene-type active ester resin, a naphthalene-type active ester resin containing a naphthalene structure, an active ester resin containing an acetylated product of phenol novolac, or an active ester resin containing a benzoylated product of phenol novolac, and among these, at least one selected from a dicyclopentadiene-type active ester resin and a naphthalene-type active ester resin is more preferred. As the dicyclopentadiene-type active ester resin, an active ester resin containing a dicyclopentadiene-type diphenol structure is preferred.

[0041] Commercially available active ester resins include, for example, activated ester resins containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "EXB-8000L", "EXB-8000L-65M", "EXB-8000L-65TM", "HPC-8000L-65TM", "HPC-8000L-65T", "HPC-8000", "HPC-8000-65T", "HPC-8000H", and "HPC-8000H-65TM" (manufactured by DIC Corporation); activated ester resins containing a naphthalene structure such as "HP-B-8151-62T", "EXB-8100L-65T", and "EXB-8150-60T"; Examples of such active ester resins include "EXB-8150-62T," "EXB-9416-70BK," "HPC-8150-60T," "HPC-8150-62T," and "EXB-8" (manufactured by DIC Corporation); "EXB9401" (manufactured by DIC Corporation) as a phosphorus-containing active ester resin; "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin which is an acetylated product of phenol novolac; "YLH1026," "YLH1030," and "YLH1048" (manufactured by Mitsubishi Chemical Corporation) as active ester resins which are benzoylated products of phenol novolac; and "PC1300-02-65MA" (manufactured by Air Water Inc.) as an active ester resin containing a styryl group and a naphthalene structure.

[0042] The cyanate resin may be a compound having one or more, preferably two or more, cyanate groups in one molecule. When combined with an epoxy resin, the cyanate resin reacts with the epoxy resin to harden the resin composition layer, and therefore is sometimes called a "cyanate-based curing agent." Examples of cyanate resins include bifunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate)), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)thioether, and bis(4-cyanatephenyl)ether; multifunctional cyanate resins derived from phenol novolac and cresol novolac; and prepolymers in which these cyanate resins are partially converted to triazine. Specific examples of cyanate resins include "PT30" and "PT60" manufactured by Arxada (both phenol novolac type multifunctional cyanate resins), "BA230" and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate has been triazine converted to a trimer).

[0043] As the carbodiimide resin, a compound having one or more, preferably two or more, carbodiimide structures in one molecule can be used. When combined with an epoxy resin, the carbodiimide resin can react with the epoxy resin to harden the resin composition layer, and therefore is sometimes called a "carbodiimide-based curing agent." Specific examples of carbodiimide resins include aliphatic biscarbodiimides such as tetramethylene-bis(t-butylcarbodiimide) and cyclohexane-bis(methylene-t-butylcarbodiimide); aromatic biscarbodiimides such as phenylene-bis(xylylcarbodiimide); aliphatic polycarbodiimides such as polyhexamethylenecarbodiimide, polytrimethylhexamethylenecarbodiimide, polycyclohexylenecarbodiimide, poly(methylenebiscyclohexylenecarbodiimide), and poly(isophoronecarbodiimide); poly(phenylenecarbodiimide), poly(naphthalenecarbodiimide); Examples of polycarbodiimides include aromatic polycarbodiimides such as poly(methylenediphenylenecarbodiimide), poly(tolylenecarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(diethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), poly(diisopropylphenylenecarbodiimide), poly(xylylenecarbodiimide), poly(tetramethylxylylenecarbodiimide), poly(methylenediphenylenecarbodiimide), and poly[methylenebis(methylphenylene)carbodiimide]. Commercially available carbodiimide resins include, for example, "Carbodilite V-02B," "Carbodilite V-03," "Carbodilite V-04K," "Carbodilite V-07," and "Carbodilite V-09" manufactured by Nisshinbo Chemical Inc.; and "Stavaxol P," "Stavaxol P400," and "Hykasil 510" manufactured by Lanxess AG.

[0044] As the acid anhydride resin, a compound having one or more, preferably two or more, acid anhydride groups in one molecule can be used. When combined with an epoxy group, the acid anhydride resin can react with the epoxy resin to harden the resin composition layer, and therefore is sometimes called an "acid anhydride curing agent." Specific examples of acid anhydride resins include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic anhydride. Examples of suitable anhydrides include hydrates, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(anhydrotrimellitate), and polymeric anhydrides such as styrene-maleic acid resin, which is a copolymer of styrene and maleic acid. Commercially available acid anhydride resins include, for example, "HNA-100," "MH-700," "MTA-15," "DDSA," and "OSA" manufactured by New Japan Chemical Co., Ltd.; "YH-306" and "YH-307" manufactured by Mitsubishi Chemical Corporation; "HN-2200" and "HN-5500" manufactured by Resonac Corporation; and "EF-30," "EF-40," "EF-60," and "EF-80" manufactured by Cray Valley Chemical Industries, Ltd.

[0045] The amine resin may be a compound having one or more, preferably two or more, amino groups in one molecule. When combined with an epoxy group, the amine resin may react with the epoxy resin to harden the resin composition layer, and is therefore sometimes referred to as an "amine-based curing agent." Examples of the amine resin include aliphatic amines, polyether amines, alicyclic amines, and aromatic amines, with aromatic amines being preferred. The amine resin is preferably a primary amine or secondary amine, with primary amines being more preferred. Specific examples of amine resins include 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, and 2,2-bis(3-amino-4-hydroxyphenyl)propionate. Examples of suitable bis(4-aminophenoxy)benzene include bis(4-aminophenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, and bis(4-(3-aminophenoxy)phenyl)sulfone. Commercially available amine resins include, for example, "SEIKACURE-S" manufactured by Seika Corporation; "KAYABOND C-200S," "KAYABOND C-100," "KAYAHARD AA," "KAYAHARD AB," and "KAYAHARD AS" manufactured by Nippon Kayaku Co., Ltd.; "Epicure W" manufactured by Mitsubishi Chemical Corporation; and "DTDA" manufactured by Sumitomo Seika Chemicals Co., Ltd.

[0046] Benzoxazine resins, when combined with epoxy resins, can react with the epoxy resin to cure the resin composition layer, and are therefore sometimes referred to as "benzoxazine-based curing agents." Specific examples of benzoxazine resins include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Corporation; "HFB2006M" manufactured by Showa Polymer Co., Ltd.; and "Pd" and "Fa" manufactured by Shikoku Chemicals Corporation.

[0047] Thiol resins, when combined with epoxy resins, can react with the epoxy resin to harden the resin composition layer, and are therefore sometimes referred to as "thiol-based curing agents." Examples of thiol resins include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and tris(3-mercaptopropyl)isocyanurate.

[0048] The active group equivalent of the curing agent as component (a) is preferably 50 g / eq. to 3000 g / eq., more preferably 100 g / eq. to 1000 g / eq., even more preferably 100 g / eq. to 500 g / eq., and particularly preferably 100 g / eq. to 300 g / eq. The active group equivalent is the mass of the curing agent per equivalent of the active group.

[0049] When the number of epoxy groups is taken as 1, the number of active groups in the curing agent is preferably 0.01 or more, more preferably 0.05 or more, even more preferably 0.1 or more, and preferably 10 or less, more preferably 5 or less, and even more preferably 3 or less. The "number of epoxy groups in the epoxy resin" refers to the total value obtained by dividing the mass of the non-volatile components of the epoxy resin present in the resin composition layer by the epoxy equivalent. Furthermore, the "number of active groups in the curing agent" refers to the total value obtained by dividing the mass of the non-volatile components of the curing agent present in the resin composition layer by the active group equivalent.

[0050] The content of the curing agent as component (a) is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, and is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass.

[0051] The content of the curing agent as component (a) is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, and is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, when the resin component in the resin composition is taken as 100% by mass.

[0052] When the curing agent as component (a) contains an active ester curing agent, the content of the active ester curing agent is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, and is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 8% by mass or less, based on 100% by mass of the non-volatile components in the resin composition.

[0053] When the curing agent as component (a) contains an active ester curing agent, the content of the active ester curing agent is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, and is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on 100% by mass of the resin component in the resin composition.

[0054] The content of the curing agent other than the active ester-based curing agent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, and is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less, based on 100% by mass of the non-volatile components in the resin composition.

[0055] The content of components other than the active ester-based curing agent is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, and is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 8% by mass or less, when the resin component in the resin composition is taken as 100% by mass.

[0056] <(b) Inorganic filler> The resin composition may contain (b) an inorganic filler as an optional component. By including (b) an inorganic filler in the resin composition, the formability of recesses can be improved. (b) The inorganic filler is usually included in the resin composition in the form of particles. The (b) component may be used alone or in combination of two or more.

[0057] (b) Inorganic compounds are used as the inorganic filler material. Examples of (b) inorganic filler materials include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium titanate zirconate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica or alumina is particularly preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Spherical silica is preferred.

[0058] (b) Examples of commercially available inorganic fillers include "SP60-05" and "SP507-05" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YC100C," "YA050C," "YA050C-MJE," "YA010C," "SC2500SQ," "SO-C4," "SO-C2," and "SO-C1" manufactured by Admatechs Co., Ltd.; "UFP-30," "DAW-03," and "FB-105FD" manufactured by Denka Co., Ltd.; "Silfil NSS-3N," "Silfil NSS-4N," and "Silfil NSS-5N" manufactured by Tokuyama Corporation; "CellSpheres" and "MGH-005" manufactured by Taiheiyo Cement Corporation; and "Sfereek" and "BA-1" manufactured by JGC Catalysts and Chemicals Co., Ltd.

[0059] (b) From the viewpoint of increasing the gradient angle of the recesses and enabling the formation of recesses with smaller diameters, the average particle size of the inorganic filler is preferably 0.01 μm or more, more preferably 0.03 μm or more, even more preferably 0.05 μm, 0.1 μm, or 0.3 μm or more, and is preferably 10 μm or less, more preferably 5 μm or less, even more preferably 3 μm or less, 2 μm or less, 1 μm or less, or 0.5 μm or less.

[0060] (b) The average particle size of an inorganic filler can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, a volumetric particle size distribution of the inorganic filler is created using a laser diffraction / scattering particle size distribution analyzer, and the median diameter is used as the average particle size. A measurement sample can be prepared by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing the mixture ultrasonically for 10 minutes. The volumetric particle size distribution of the inorganic filler is measured using a laser diffraction particle size distribution analyzer with blue and red light source wavelengths using a flow cell system, and the average particle size can be calculated as the median diameter from the particle size distribution obtained. Examples of laser diffraction particle size distribution analyzers include the LA-960 manufactured by Horiba, Ltd.

[0061] (b) The BET specific surface area of ​​the inorganic filler is preferably 0.1 m 2 / g or more, more preferably 0.5m 2 / g or more, more preferably 1m 2 / g or more, preferably 100m 2 / g or less, more preferably 70m 2 / g or less, more preferably 40m 2 / g or less.

[0062] (b) The specific surface area of ​​the inorganic filler can be measured according to the BET method by adsorbing nitrogen gas onto the sample surface using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) and calculating the specific surface area using the BET multipoint method.

[0063] (b) The inorganic filler is preferably treated with a surface treatment agent from the viewpoint of improving moisture resistance and dispersibility. Examples of the surface treatment agent include a fluorine-containing silane coupling agent, an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a silane coupling agent, an alkoxysilane, an organosilazane compound, and a titanate coupling agent. One type of surface treatment agent may be used alone, or two or more types may be used in any combination.

[0064] Examples of commercially available surface treatment agents include Shin-Etsu Chemical Co., Ltd.'s "KBM403" (3-glycidoxypropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM803" (3-mercaptopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd.'s "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy-type silane coupling agent), and Shin-Etsu Chemical Co., Ltd.'s "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane).

[0065] The degree of surface treatment with the surface treatment agent preferably falls within a specific range from the viewpoint of improving the dispersibility of the inorganic filler. Specifically, 100% by mass of the inorganic filler is preferably surface-treated with 0.2% to 5% by mass of the surface treatment agent, more preferably with 0.2% to 3% by mass of the surface treatment agent, and even more preferably with 0.3% to 2% by mass of the surface treatment agent.

[0066] The degree of surface treatment with the surface treatment agent can be evaluated by the amount of carbon per unit surface area of ​​the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of ​​the inorganic filler is set to 0.02 mg / m 2 More than 0.1 mg / m is preferable. 2 More preferably, 0.2 mg / m or more 2 On the other hand, from the viewpoint of preventing an increase in the melt viscosity of the resin composition, it is more preferable that the content be 1.0 mg / m 2 Preferably less than 0.8 mg / m 2 Less than 0.5 mg / m is more preferable. 2 The following is even more preferred:

[0067] (b) The amount of carbon per unit surface area of ​​the inorganic filler can be measured after the surface-treated inorganic filler is washed with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solid content, the amount of carbon per unit surface area of ​​the inorganic filler can be measured using a carbon analyzer. The carbon analyzer that can be used is the "EMIA-320V" manufactured by Horiba, Ltd.

[0068] The degree of surface treatment with a surface treatment agent can be evaluated by the amount of carbon per unit mass of the inorganic filler. The amount of carbon per unit mass of the inorganic filler is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, and is preferably 1.0% by mass or less, more preferably 0.8% by mass or less, and even more preferably 0.5% by mass or less. The amount of carbon per unit mass of (b) the inorganic filler can be measured using a carbon analyzer, just like the amount of carbon per unit surface area of ​​(b) the inorganic filler.

[0069] From the viewpoint of increasing the gradient angle of the recesses and enabling the formation of recesses with smaller diameters, the content of (b) inorganic filler is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 35% by mass or more, or 40% by mass or more, and is preferably 85% by mass or less, more preferably 80% by mass or less, even more preferably 75% by mass or less, when the non-volatile components in the resin composition are taken as 100% by mass.

[0070] <(c) Thermoplastic resin> The resin composition may further contain a (c) thermoplastic resin as an optional component. The (c) thermoplastic resin as component (c) does not include those corresponding to the above-mentioned components (a) and (b). The (c) thermoplastic resin may be used alone or in combination of two or more.

[0071] Examples of the (c) thermoplastic resin include phenoxy resin, polystyrene resin, polyimide resin, polyvinyl acetal resin, polyolefin resin, polybutadiene resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polycarbonate resin, polyetheretherketone resin, polyester resin, etc. In one embodiment, the (c) thermoplastic resin preferably includes a phenoxy resin.

[0072] Examples of phenoxy resins include phenoxy resins having one or more skeletons selected from the group consisting of bisphenol A, bisphenol F, bisphenol S, bisphenolacetophenone, novolac, biphenyl, fluorene, dicyclopentadiene, norbornene, naphthalene, anthracene, adamantane, terpene, and trimethylcyclohexane. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group.

[0073] Specific examples of phenoxy resins include "1256" and "4250" manufactured by Mitsubishi Chemical Corporation (both of which are phenoxy resins containing a bisphenol A skeleton); "YX8100" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing a bisphenol S skeleton); "YX6954" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing a bisphenol acetophenone skeleton); "FX280" and "FX293" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; and "YL7500BH30," "YX6954BH30," "YX7553," "YX7553BH30," "YL7769BH30," "YL6794," "YL7213," "YL7290," "YL7482," and "YL7891BH30" manufactured by Mitsubishi Chemical Corporation.

[0074] The polystyrene resin may be a commercially available product, and examples thereof include hydrogenated styrene-based thermoplastic elastomers "H1041," "Tuftec H1043," "Tuftec P2000," and "Tuftec MP10" (manufactured by Asahi Kasei Corporation); epoxidized styrene-butadiene thermoplastic elastomers "Epofriend AT501" and "CT310" (manufactured by Daicel Corporation); modified styrene-based elastomer having a hydroxyl group "Septon HG252" (manufactured by Kuraray Co., Ltd.); modified styrene-based elastomer having a carboxyl group "Tuftec N503M," modified styrene-based elastomer having an amino group "Tuftec N501," modified styrene-based elastomer having an acid anhydride group "Tuftec M1913" (manufactured by Asahi Kasei Corporation); and unmodified styrene-based elastomer "Septon S8104" (manufactured by Kuraray Co., Ltd.).

[0075] Specific examples of polyimide resins include "SLK-6100" manufactured by Shin-Etsu Chemical Co., Ltd., and "Rikacoat SN20" and "Rikacoat PN20" manufactured by New Japan Chemical Co., Ltd.

[0076] Examples of polyvinyl acetal resins include polyvinyl formal resins and polyvinyl butyral resins, with polyvinyl butyral resins being preferred. Specific examples of polyvinyl acetal resins include S-LEC BH series, BX series (e.g., BX-5Z), KS series (e.g., KS-1), BL series, and BM series manufactured by Sekisui Chemical Co., Ltd.

[0077] Examples of polyolefin resins include ethylene copolymer resins such as low-density polyethylene, very low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer; and polyolefin polymers such as polypropylene and ethylene-propylene block copolymer.

[0078] Examples of polybutadiene resins include hydrogenated polybutadiene skeleton-containing resins, hydroxy group-containing polybutadiene resins, phenolic hydroxy group-containing polybutadiene resins, carboxy group-containing polybutadiene resins, acid anhydride group-containing polybutadiene resins, epoxy group-containing polybutadiene resins, isocyanate group-containing polybutadiene resins, urethane group-containing polybutadiene resins, and polyphenylene ether-polybutadiene resins.

[0079] Specific examples of polyamide-imide resins include "Vylomax HR11NN" and "Vylomax HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of polyamide-imide resins also include modified polyamide-imides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamide-imides) manufactured by Resonac Corporation.

[0080] A specific example of the polyethersulfone resin is "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

[0081] Specific examples of polysulfone resins include polysulfones "P1700" and "P3500" manufactured by Solvay Advanced Polymers.

[0082] A specific example of the polyphenylene ether resin is NORYL SA90 manufactured by SABIC, etc. A specific example of the polyetherimide resin is ULTEM manufactured by GE, etc.

[0083] Examples of polycarbonate resins include hydroxyl group-containing carbonate resins, phenolic hydroxyl group-containing carbonate resins, carboxyl group-containing carbonate resins, acid anhydride group-containing carbonate resins, isocyanate group-containing carbonate resins, and urethane group-containing carbonate resins. Specific examples of polycarbonate resins include "FPC0220" manufactured by Mitsubishi Gas Chemical Company, Inc., "T6002" and "T6001" (polycarbonate diols) manufactured by Asahi Kasei Corporation, and "C-1090," "C-2090," and "C-3090" (polycarbonate diols) manufactured by Kuraray Co., Ltd. Specific examples of polyether ether ketone resins include "Sumiploy K" manufactured by Sumitomo Chemical Co., Ltd.

[0084] Examples of polyester resins include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, and polycyclohexane dimethyl terephthalate resin.

[0085] From the viewpoint of significantly achieving the effects of the present invention, the weight average molecular weight (Mw) of the (c) thermoplastic resin is preferably 5,000 or more, more preferably 8,000 or more, even more preferably 10,000 or more, and particularly preferably 20,000 or more, and is preferably 100,000 or less, more preferably 70,000 or less, even more preferably 60,000 or less, and particularly preferably 50,000 or less.

[0086] The content of (c) the thermoplastic resin is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more, and is preferably 15% by mass or less, more preferably 12% by mass or less, and even more preferably 10% by mass or less, assuming that the non-volatile components in the resin composition are 100% by mass.

[0087] The content of (c) the thermoplastic resin is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, assuming that the resin component in the resin composition is 100% by mass.

[0088] <(d) Curing accelerator> The resin composition may further contain a (d) curing accelerator as an optional component. The (d) curing accelerator as component (d) does not include those corresponding to the above-mentioned components (a) to (c). The (d) curing accelerator functions as a curing catalyst that accelerates the curing of the (d) epoxy resin. The (d) component may be used alone or in combination of two or more.

[0089] Examples of the (d) curing accelerator include phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, imidazole-based curing accelerators, metal-based curing accelerators, and amine-based curing accelerators. Of these, it is preferable to use either a phosphorus-based curing accelerator or an imidazole-based curing accelerator. One type of (d) curing accelerator may be used alone, or two or more types may be used in combination.

[0090] Examples of the phosphorus-based curing accelerator include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium)pyromellitate, tetrabutylphosphonium hydrogenhexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butyldimethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, and tetraphenylphosphonium tetra-p-tolylborate. aromatic phosphonium salts such as tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone adducts such as triphenylphosphine-p-benzoquinone adduct; aliphatic phosphines such as tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, and tricyclohexylphosphine;Dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine aromatic phosphines such as benzene, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, and 2,2'-bis(diphenylphosphino)diphenyl ether;

[0091] Examples of the urea-based curing accelerator include 1,1-dimethylurea; aliphatic dimethylureas such as 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, and 3-(3,4-dimethylphenyl)-1,1-dimethylurea. aromatic dimethylureas such as toluene bis(dimethylurea), 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N',N'-dimethylurea), and N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea) [toluene bisdimethylurea].

[0092] Examples of guanidine curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, and 1-(o-tolyl)biguanide.

[0093] Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-methylimidazole. Phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl -(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct Examples of imidazole compounds include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds with epoxy resins. Commercially available imidazole curing accelerators include "1B2PZ," "2E4MZ," "2MZA-PW," "2MZ-OK," "2MA-OK," "2MA-OK-PW," "2PHZ," "2PHZ-PW," "Cl1Z," "Cl1Z-CN," "Cl1Z-CNS," and "C11Z-A" manufactured by Shikoku Chemicals Corporation; and "P200-H50" manufactured by Mitsubishi Chemical Corporation.

[0094] Examples of metal-based curing accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organic cobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organic copper complexes such as copper(II) acetylacetonate, organic zinc complexes such as zinc(II) acetylacetonate, organic iron complexes such as iron(III) acetylacetonate, organic nickel complexes such as nickel(II) acetylacetonate, and organic manganese complexes such as manganese(II) acetylacetonate. Examples of organometallic salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0095] Examples of the amine curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, etc. Commercially available amine curing accelerators may be used, such as "MY-25" manufactured by Ajinomoto Fine-Techno Co., Inc.

[0096] The content of (d) the curing accelerator is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.03% by mass or more, and is preferably 2.0% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1.0% by mass or less, when the non-volatile components of the resin composition are taken as 100% by mass.

[0097] The content of (d) the curing accelerator, when the resin component of the resin composition is taken as 100% by mass, is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, and is preferably 3% by mass or less, more preferably 2.5% by mass or less, even more preferably 2.0% by mass or less.

[0098] <(e) Optional Additives> The resin composition may contain (e) an optional additive as an optional component. Examples of the optional additive (e) include organic fillers such as rubber particles; elastomers (excluding those corresponding to component (c)); organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; thickeners such as bentone and montmorillonite; antifoaming agents such as silicone-based antifoaming agents, acrylic-based antifoaming agents, fluorine-based antifoaming agents, and vinyl resin-based antifoaming agents; ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers; adhesion improvers such as urea silane; triazole-based adhesion promoters, tetrazole-based antifoaming agents, and the like. Examples of the additives include adhesion promoters such as phenol-based adhesion promoters and triazine-based adhesion promoters; antioxidants such as hindered phenol-based antioxidants; fluorescent brighteners such as stilbene derivatives; surfactants such as fluorine-based surfactants and silicone-based surfactants; flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, and red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g., antimony trioxide); dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants; and stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic anhydride-based stabilizers. (e) Optional additives may be used alone or in combination of two or more.

[0099] <(f) Solvent> The resin composition may further contain (f) a solvent as an optional volatile component in addition to the non-volatile components (a) to (e) described above. The (f) solvent is typically an organic solvent. Examples of the organic solvent include ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether-based solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, diphenyl ether, and anisole; alcohol-based solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate. Examples of suitable solvents include ether ester solvents such as ethyl acetate; ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. (f) The solvent may be used alone or in combination of two or more.

[0100] The amount of (f) solvent is not particularly limited, but may be, for example, 60% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, or even 0% by mass, relative to 100% by mass of all components of the resin composition.

[0101] The resin composition can be produced, for example, by mixing the above-mentioned components. Some or all of the above-mentioned components may be mixed simultaneously, or they may be mixed sequentially. In the process of mixing each component, the temperature may be appropriately set, and thus heating and / or cooling may be performed temporarily or throughout. Furthermore, stirring or shaking may be performed in the process of mixing each component.

[0102] The tensile modulus of the cured product obtained by curing the resin composition under curing conditions of 180°C and 90 minutes is preferably 1 GPa or more, more preferably 1.5 GPa or more, even more preferably 2 GPa or more, from the viewpoint of improving processability in wet blasting and improving the formability of recesses, and is preferably 20 GPa or less, more preferably 18 GPa or less, and even more preferably 16 GPa or less. The tensile modulus can be measured by the method described in the examples below.

[0103] [Resin sheet] The resin sheet includes a support and a resin composition layer formed from a resin composition provided on the support.

[0104] The thickness of the resin composition layer is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 50 μm or less, from the viewpoint of making the wiring board thinner and being able to provide a cured product of the resin composition with excellent insulating properties even when the cured product is a thin film. The lower limit of the thickness of the resin composition layer is not particularly limited, but can usually be 5 μm or more.

[0105] Examples of the support include films made of plastic materials, metal foils, and release papers, with films made of plastic materials and metal foils being preferred.

[0106] When a film made of a plastic material is used as the support, examples of the plastic material include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, with inexpensive polyethylene terephthalate being particularly preferred.

[0107] When a metal foil is used as the support, examples of the metal foil include copper foil and aluminum foil, with copper foil being preferred. The copper foil may be a foil made of a single metal, copper, or an alloy of copper and another metal (e.g., tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.).

[0108] The surface of the support that is to be bonded to the resin composition layer may be subjected to a matte treatment, a corona treatment, or an antistatic treatment.

[0109] The support may also be a support with a release layer, which has a release layer on the surface that bonds to the resin composition layer. Examples of the release agent used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. Commercially available products may also be used as the support with a release layer, including, for example, "SK-1," "AL-5," and "AL-7" manufactured by Lintec Corporation, "Lumirror T60" manufactured by Toray Industries, Inc., "Purex" manufactured by Teijin Limited, and "Uni-Peel" manufactured by Unitika Limited, which are PET films having a release layer primarily composed of an alkyd resin-based release agent.

[0110] The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, more preferably 10 μm to 60 μm. When a support with a release layer is used, it is preferable that the thickness of the entire support with a release layer is in the above range.

[0111] In one embodiment, the resin sheet may further include other layers as necessary. Examples of such other layers include a protective film conforming to the support and provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, adhesion of dust and the like to the surface of the resin composition layer and scratches can be suppressed.

[0112] The resin sheet can be produced, for example, by preparing a resin varnish by dissolving a resin composition in a solvent, applying the resin varnish to a support using a die coater or the like, and then drying the applied resin varnish to form a resin composition layer. The solvent is as described above.

[0113] Drying may be carried out by known methods such as heating or hot air blowing. Drying conditions are not particularly limited, but drying is carried out so that the solvent content in the resin composition layer becomes 10% by mass or less, preferably 5% by mass or less. Although this varies depending on the boiling point of the solvent in the resin varnish, for example, when a resin varnish containing 30% by mass to 60% by mass of solvent is used, the resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

[0114] The resin sheet can be stored in a rolled state. When the resin sheet has a protective film, it can be used by peeling off the protective film.

[0115] [Manufacturing method for wiring boards] The method for manufacturing a wiring board of the present invention comprises the steps of: (A) forming an insulating layer containing a cured product of a resin composition and a thermoplastic resin layer in this order on a substrate; (B) forming a mask pattern on the thermoplastic resin layer; and and (C) a step of wet-blasting using abrasive grains to form recesses in the thermoplastic resin layer and the insulating layer. Steps (A), (B), and (C) are preferably performed in this order. By performing steps (A) to (C), it is possible to manufacture a wiring board that has excellent recess formability and minimizes step differences in the cross-sectional shape. Furthermore, it is usually possible to minimize abrasive grain residue at the bottom of the recess, and increase the slope angle of the recess, thereby enabling the opening diameter of the recess to be smaller. The slope angle of the recess refers to the angle between the bottom of the recess and the wall surface of the recess. Specifically, it refers to the angle θ between the bottom of via hole 100 and the wall surface of via hole 100, as shown in an example in FIG. 8.

[0116] As shown in FIG. 8 , a wiring board 1 obtained by the manufacturing method of the present invention includes a substrate 10, an insulating layer 20, and a thermoplastic resin layer 30, in this order. The thermoplastic resin layer 30 has a first surface 30a, which is the surface facing the insulating layer 20, and a second surface 30b, which is the surface opposite the first surface 30a. Because the insulating layer 20 is in contact with the first surface 30a of the thermoplastic resin layer 30, there are typically no other layers between the thermoplastic resin layer 30 and the insulating layer 20. The insulating layer 20 and the thermoplastic resin layer 30 each have a via hole 100 formed therethrough in the thickness direction. The via hole 100 is generally used for electrical connection between a conductor layer (not shown) formed on the thermoplastic resin layer and a metal layer (not shown), such as wiring, provided on the substrate 10. While the via hole 100 is formed as a recess in FIG. 8 , it may also be a trench.

[0117] <Process (A)> In step (A), as shown in an example in Figure 1, a resin composition layer 20a and a thermosetting resin layer 30 are laminated in this order on a substrate 10, and the resin composition layer 20a is thermally cured to form an insulating layer. That is, an insulating layer and a thermoplastic resin layer are formed in this order on the substrate. The insulating layer used in the wiring board of the present invention functions not only as an insulating layer that insulates each layer, but also as a bonding sheet that bonds the substrate and the thermoplastic resin layer.

[0118] As a preferred embodiment of step (A), (A-1) a step of preparing a substrate; (A-2) a step of preparing a resin sheet including a support and a resin composition layer provided on the support; (A-3) a step of laminating a resin composition layer on a substrate to form a resin composition layer; (A-4) forming a thermoplastic resin layer on the resin composition layer; and It is preferable to include a step (A-5) of curing the resin composition layer to form an insulating layer.

[0119] Examples of the substrate include silicon wafers; glass wafers; glass substrates; metal substrates such as copper, titanium, stainless steel, and cold-rolled steel sheets (SPCC); substrates such as FR-4 substrates in which glass fibers are impregnated with epoxy resin or the like and then thermoset; and substrates made of bismaleimide triazine resins such as BT resin.

[0120] The substrate may also be an inner layer substrate. An inner layer substrate is a member that serves as the substrate of a wiring board, and examples thereof include a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, and a thermosetting polyphenylene ether substrate. The substrate may have a conductor layer on one or both sides, and this conductor layer may be patterned. An inner layer substrate having a conductor layer (circuit) formed on one or both sides of the substrate may be referred to as an "inner layer circuit board." In addition, an intermediate product on which an insulating layer and / or a conductor layer is to be further formed during the production of a wiring board is also included in the inner layer substrate of the present invention. For example, when the printed wiring board is a circuit board with built-in components, an inner layer substrate with built-in components may be used.

[0121] The arithmetic mean roughness (Ra) of the main surface of the substrate is preferably 1000 nm or less, more preferably 750 nm or less, even more preferably 600 nm or less, or even 500 nm or less. By keeping the arithmetic mean roughness (Ra) of the main surface of the substrate within this range, it is possible to prevent the insulating layer formed on the main surface from penetrating deep into the substrate, thereby improving the processability of recesses. While there is no particular lower limit, it is preferably 10 nm or more, more preferably 15 nm or more, and even more preferably 20 nm or more. The arithmetic mean roughness (Ra) of the main surface of the substrate is a value measured in accordance with ISO 25178 and can be measured using a non-contact surface roughness meter. The main surface of the substrate refers to the surface of the substrate on which the insulating layer is formed. Note that if the arithmetic mean roughness (Ra) is not constant across the main surface, it is sufficient that the arithmetic mean roughness (Ra) of the main surface in the area where the insulating layer is formed is within the above-mentioned range, and it is preferable that the arithmetic mean roughness (Ra) of the main surface in the area where the recesses are formed be within the above-mentioned range.

[0122] The resin sheet in the step (A-2) is as explained above.

[0123] In step (A-3), a resin composition layer is laminated on a substrate. The lamination of the substrate and the resin sheet can be performed, for example, by thermocompression bonding the resin sheet to the substrate from the support side. Examples of a member for thermocompression bonding the resin sheet to the substrate (hereinafter also referred to as a "thermocompression bonding member") include a heated metal plate (such as a SUS panel) or a metal roll (such as a SUS roll). It is preferable to press the thermocompression bonding member not directly onto the resin sheet, but via an elastic material such as heat-resistant rubber so that the resin sheet can sufficiently conform to the surface irregularities of the substrate.

[0124] The substrate and the resin sheet may be laminated by a vacuum lamination method. In the vacuum lamination method, the thermocompression temperature is preferably in the range of 60°C to 160°C, more preferably 80°C to 140°C, the thermocompression pressure is preferably in the range of 0.098MPa to 1.77MPa, more preferably 0.29MPa to 1.47MPa, and the thermocompression time is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. The lamination is preferably carried out under reduced pressure conditions of 26.7hPa or less.

[0125] The lamination can be performed using a commercially available vacuum laminator, such as a vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd., a vacuum applicator manufactured by Nikko Materials Co., Ltd., or a batch vacuum pressure laminator.

[0126] After lamination, the laminated resin sheets may be smoothed under normal pressure (atmospheric pressure), for example, by pressing a thermocompression member from the support side. The pressing conditions for the smoothing treatment may be the same as the thermocompression conditions for lamination. The smoothing treatment may be performed using a commercially available laminator. Note that lamination and smoothing treatment may be performed consecutively using the commercially available vacuum laminator.

[0127] The support may be removed between step (A-2) and step (A-3), or may be removed after step (A-3).

[0128] Instead of step (A-3), a step of forming a resin composition layer by applying a resin composition to a substrate and drying it may be performed. The resin composition can be applied using an appropriate application device such as a die coater. The resin composition layer may be dried by heating, blowing hot air, or other methods. The drying conditions are not particularly limited, but the resin composition is usually dried so that the solvent content in the resin composition is 10% by mass or less, preferably 5% by mass or less. Although this varies depending on the boiling point of the solvent in the resin composition, for example, when a resin composition containing 30% by mass to 60% by mass of solvent is applied, a resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

[0129] In step (A-4), a thermoplastic resin layer is formed on the resin composition layer. Specifically, a film-like thermoplastic resin layer (a resin sheet for forming a thermoplastic resin layer) is laminated on the resin composition layer. The lamination of the resin composition layer and the thermoplastic resin layer can be performed under the same conditions as those for laminating the substrate and the resin sheet in step (A-3). Alternatively, a resin varnish may be prepared by dissolving the material for the thermoplastic resin layer in an organic solvent, and the resin varnish may be applied to the resin composition layer using a die coater or the like, and then dried to form a thermoplastic resin layer. The organic solvent and the like are as described above.

[0130] The thermoplastic resin layer is preferably formed of a thermoplastic resin. Examples of materials for the thermoplastic resin layer include polyimide, liquid crystal polymer, polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyether ether ketone, polybenzimidazole, aramid, polyamideimide, and polyetherimide. Among these, the material for the thermoplastic resin layer is preferably either a polyimide resin or a liquid crystal polymer, and more preferably polyimide.

[0131] The surface of the thermoplastic resin layer may be subjected to corona treatment, plasma treatment, or UV treatment. Use of such a thermoplastic resin layer can enhance the adhesion between the thermoplastic resin layer and the insulating layer. The conditions for the corona treatment, plasma treatment, or UV treatment may be determined appropriately depending on the material of the thermoplastic resin layer, etc.

[0132] In step (A), a laminate having a thermoplastic resin layer and a metal foil such as copper foil laminated thereon may be laminated on the resin composition layer so that the thermoplastic resin layer faces the side of the resin composition layer that is not bonded to the support, thereby forming a thermoplastic resin layer on the resin composition layer. When step (A) is performed using this laminate, the mask pattern formed in step (B) described below is preferably formed by a subtractive method using a metal foil.

[0133] The thermoplastic resin layer may be a commercially available product, such as "Vecstar-FCCL:CTF-25" manufactured by Kuraray Co., Ltd., a polyimide copper-clad laminate (ESPANEX: MC12-25-00HRM, manufactured by Nippon Steel Chemical Co., Ltd.), a polyimide film (Kapton, manufactured by Toray DuPont Co., Ltd.), or a polyimide (UPILEX S, manufactured by UBE).

[0134] In step (A-5), the resin composition layer is cured to form an insulating layer made of a cured product of the resin composition layer. The resin composition layer is usually cured by thermal curing. Specific curing conditions for the resin composition layer may be those typically used when forming an insulating layer for a printed wiring board.

[0135] For example, the thermal curing conditions for the resin composition layer vary depending on the types of components contained in the resin composition layer, but in one embodiment, the curing temperature is preferably 120° C. to 240° C., more preferably 150° C. to 220° C., and even more preferably 170° C. to 210° C. The curing time is preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, and even more preferably 15 minutes to 100 minutes.

[0136] Before thermally curing the resin composition layer, the resin composition layer may be preheated at a temperature lower than the curing temperature. For example, prior to thermally curing the resin composition layer, the resin composition layer may be preheated at a temperature of 50°C to 150°C, preferably 60°C to 140°C, more preferably 70°C to 130°C for 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes.

[0137] The thickness of the insulating layer is preferably 100 μm or less, more preferably 50 μm or less, further preferably 40 μm or less, 30 μm or less, or 20 μm or less, and is preferably 1 μm or more, more preferably 5 μm or more.

[0138] The thickness of the thermoplastic resin layer is preferably 100 μm or less, more preferably 50 μm or less, further preferably 40 μm or less, 30 μm or less, or 20 μm or less, and is preferably 1 μm or more, more preferably 5 μm or more.

[0139] The total thickness of the insulating layer and the thermoplastic resin layer is preferably 200 μm or less, more preferably 100 μm or less, even more preferably 80 μm or less, 60 μm or less, or 40 μm or less, and is preferably 2 μm or more, more preferably 6 μm or more, and even more preferably 10 μm or more.

[0140] When the thickness of the thermoplastic resin layer is b and the thickness of the insulating layer is c, b / c is preferably 0.5 or more, more preferably 1 or more, and even more preferably 1.5 or more, and is preferably 10 or less, more preferably 5 or less, and even more preferably 3 or less, or 2 or less.

[0141] <Process (B)> Step (B) is a step of forming a mask pattern 40 having openings 41 on the thermoplastic resin layer 30, as shown in an example in Fig. 6. The mask pattern 40 is preferably resistant to the wet blasting treatment in step (C) described below. Therefore, from the viewpoint of improving via formation properties, the mask pattern 40 is preferably a metal mask pattern.

[0142] Examples of metals that can form the metal mask pattern include copper, nickel, tin, zinc, iron, and alloys thereof. Among these, copper is preferred from the viewpoint of resistance to the wet blasting treatment in the step (C) described below.

[0143] The method for forming the mask pattern is not particularly limited. In one embodiment of step (B), (B-1) forming a metal layer to serve as a mask on a thermoplastic resin layer; (B-2) forming a photosensitive layer having openings on the metal layer; (B-3) etching the exposed metal layer to form a metal mask pattern; and (B-4) a step of removing the photosensitive layer.

[0144] In the step (B-1), a metal layer 40 is formed on a thermoplastic resin layer 30, as shown in an example in FIG.

[0145] Examples of methods for forming the metal layer that serves as a mask include electroplating, subtractive, and semi-additive methods, among which electroplating is preferred to form the metal layer, from the viewpoint of obtaining a mask pattern that is resistant to the wet blasting treatment in step (C) described below and improving recess formability.

[0146] When a metal layer is formed by electroplating, the metal layer is usually formed on the surface of a thermoplastic resin layer in a plating solution containing metal ions. For example, the thermoplastic resin layer is placed in the plating solution, and a direct current is applied from a power source between the thermoplastic resin layer and an electrode. Metal ions are reduced on the surface of the thermoplastic resin layer, causing the metal to precipitate, forming a metal layer containing the metal. Copper is preferred as the metal used for electroplating.

[0147] Typically, an aqueous solution of a metal salt is used as the plating solution. There are no limitations on the metal salt as long as it allows for the formation of a metal layer by electroplating. For example, when copper is used as the metal, examples of the copper salt include copper sulfate such as copper sulfate pentahydrate, copper halides such as copper chloride, copper acetate, copper nitrate, copper tetrafluoroborate, copper alkylsulfonate, copper arylsulfonate, copper sulfamate, copper perchlorate, and copper gluconate. Among these, copper sulfate is preferred. The concentration of the metal salt in the plating solution can be, for example, 50 g / L or more and 400 g / L or less. It is more preferred that the concentration of the metal salt in the plating solution be a saturated concentration.

[0148] The plating solution preferably contains an acid. Examples of acids include sulfuric acid; hydrochloric acid; acetic acid; nitric acid; phosphoric acid; fluoroboric acid; alkanesulfonic acids such as methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, and trifluoromethanesulfonic acid; arylsulfonic acids such as benzenesulfonic acid, p-toluenesulfonic acid, and sulfamic acid; hydrobromic acid; perchloric acid; and chromic acid. Among these, sulfuric acid, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, hydrochloric acid, and combinations thereof are preferred, with sulfuric acid being more preferred. The concentration of the acid in the plating solution can be, for example, 1 mL / L or more and 400 mL / L or less. When sulfuric acid is used, the concentration of sulfuric acid is preferably 40 mL / L or more and 200 mL / L or less.

[0149] The plating solution may contain additives. Examples of additives that may be contained in the plating solution include a halide ion supplier, a brightener, and a surfactant. Examples of halide ion suppliers include chlorine compounds such as sodium chloride and potassium chloride. The concentration of the halide ion supplier in the plating solution may be, for example, 0.5 mg / L to 300 mg / L. Examples of brighteners include organic sulfur compounds such as bis(3-sulfopropyl)disulfide salts. The concentration of the brightener in the plating solution may be, for example, 0.1 ppm to 1000 ppm. Examples of surfactants include anionic surfactants, cationic surfactants, and nonionic surfactants. The concentration of the surfactant in the plating solution may be, for example, 1 mL / L to 60 mL / L.

[0150] The temperature of the plating solution is not limited as long as it can form a metal layer, and is preferably 2°C or higher, more preferably 10°C or higher, even more preferably 15°C or higher, and is preferably 80°C or lower, more preferably 50°C or lower, even more preferably 30°C or lower.

[0151] The current density of the current applied during electroplating is not limited as long as it can form a metal layer, and is preferably 0.5 A / dm 2 More than 1.0A / dm is preferable. 2 or more, preferably 8.0A / dm 2 Less than or equal to 7.0A / dm is preferable. 2 The following is the result.

[0152] Electroplating may be performed in a state where a plating solution is flowing through the plating solution. The flow rate of the plating solution may be, for example, 3 cm / sec or more and 200 cm / sec or less.

[0153] When forming a metal layer by a subtractive method, a laminate in which a thermoplastic resin layer and a metal foil such as copper foil are laminated is used, and the metal foil is used as the metal layer.

[0154] When forming a metal layer using the semi-additive method, a plating seed layer is formed on the surface of a thermoplastic resin layer by electroless plating or sputtering. Then, patterning is performed on the plating seed layer using a dry film resist, and an electroplated layer is formed by electroplating. After peeling off the dry film, the plating seed layer is removed by etching, and the metal layer is formed.

[0155] The method for forming a metal layer by electroless plating involves a pre-dip process to adjust the surface charge of a thermoplastic resin layer in order to apply palladium to the surface of the thermoplastic resin layer. Next, palladium, an activator, is applied to the surface, and the palladium applied to the thermoplastic resin layer is reduced. Next, a metal such as copper is deposited on the surface of the thermoplastic resin layer to form a plating seed layer.

[0156] The method for forming the plating seed layer by sputtering is the same as the method for forming the metal seed layer in step (Ba) described below.

[0157] In step (B-2), a photosensitive layer having an opening is formed on the metal layer. More specifically, a photosensitive layer 50 is formed on the metal layer 40, as shown in an example in FIG. 3. After forming the photosensitive layer 50, the photosensitive layer 50 is patterned to form the photosensitive layer 50 having an opening 51, as shown in an example in FIG.

[0158] The patterning may be performed by, for example, exposure and development, or by etching.

[0159] The photosensitive layer may be formed by applying a photoresist composition onto the metal layer. Examples of photoresist compositions include novolac resin compositions and acrylic resin compositions. After forming the photoresist layer, exposure is performed by irradiating the photoresist layer with active energy rays through a photomask having the desired pattern shape. Specifically, the surface of the photosensitive layer is irradiated with active energy rays through a photomask corresponding to the desired mask pattern shape, thereby photocuring the exposed portion of the photosensitive layer. Examples of active energy rays include ultraviolet rays, visible light, electron beams, and X-rays, with ultraviolet rays being preferred. The dose and duration of ultraviolet light irradiation can be appropriately set depending on the photosensitive layer. Examples of exposure methods include contact exposure, in which a mask pattern is exposed by adhering it to a dry film, and non-contact exposure, in which a mask pattern is exposed using parallel light without being adhering it to a dry film.

[0160] After exposure, development is performed to remove the exposed portions of the photosensitive layer, thereby forming a photosensitive layer having openings (patterned photosensitive layer). Development may be performed by either wet development or dry development. Examples of development methods include a dipping method, a puddle method, a spray method, a brushing method, and a scraping method.

[0161] The photosensitive layer may be formed by laminating a dry film. A photosensitive dry film may be used as the dry film. Commercially available dry films may be used, such as "RY-5115" manufactured by Resonac Corporation or "ALPHO 20A263" manufactured by Nikko Materials Co., Ltd.

[0162] When the photosensitive layer is a dry film, the dry film is laminated on the metal layer, and is exposed to active energy rays through a photomask having a pattern to be formed, followed by development. The exposure and development are the same as when the photosensitive layer is a photoresist composition.

[0163] The top diameter of the openings in the photosensitive layer is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less. There is no particular lower limit, but it is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. The top diameter of the openings in the photosensitive layer is the opening diameter of the opening, and refers to the diameter of the opening on the surface opposite to the side in contact with the metal layer. The top diameter can be determined by observing the cross section using an SEM.

[0164] After forming the photosensitive layer having openings in step (B-2), a descum treatment using plasma may be carried out as needed to remove resin residues remaining on the surface of the photosensitive layer having openings.

[0165] In the step (B-3), as shown in FIG. 5, the metal layer 40 exposed from the openings 51 in the photosensitive layer 50 is etched to form a mask pattern (metal mask pattern) 40′ having openings 41.

[0166] The etching solution used for etching is preferably one or more selected from the group consisting of an etching solution containing any one of hydrogen peroxide, sulfuric acid, and nitric acid; an etching solution containing a fluoride; an etching solution containing hydrogen peroxide and aqueous ammonia; and an etching solution containing any one of copper sulfate, iron sulfate, and copper chloride. Note that, when the metal layer contains copper, the etching solution is preferably one or more selected from an etching solution containing any one of hydrogen peroxide, sulfuric acid, and nitric acid; an etching solution containing a fluoride; an etching solution containing hydrogen peroxide and aqueous ammonia; and an etching solution containing any one of copper sulfate, iron sulfate, and copper chloride.

[0167] Examples of etching solutions containing any of hydrogen peroxide, sulfuric acid, and nitric acid include etching solutions containing sulfuric acid and hydrogen peroxide, and etching solutions containing nitric acid and hydrogen peroxide. Commercially available etching solutions containing any of hydrogen peroxide, sulfuric acid, and nitric acid can be used. Examples of commercially available products include "NH-1866" (etching solution containing nitric acid and hydrogen peroxide) manufactured by MEC Corporation, "SAC" (etching solution containing sulfuric acid and hydrogen peroxide) manufactured by JCU Corporation, and "CPE-800D" manufactured by Mitsubishi Gas Chemical Company, Inc.

[0168] An example of an etching solution containing fluoride is an aqueous solution containing 1% by weight of hydrogen peroxide and 1% by weight of hydrofluoric acid. Commercially available etching solutions containing fluoride can be used, such as "Clean Etch Putax" manufactured by Mitsubishi Gas Chemical Company, Inc.

[0169] The etching solution containing hydrogen peroxide and aqueous ammonia can be an alkaline etching solution whose pH is adjusted with aqueous ammonia. The pH is preferably 7.1 or higher, more preferably 7.3 or higher, and even more preferably 7.5 or higher, and is preferably 14 or lower, more preferably 13 or lower, and even more preferably 10 or lower. A commercially available product can be used as the etching solution containing hydrogen peroxide and aqueous ammonia. An example of a commercially available product is "WCT-T" manufactured by Mitsubishi Gas Chemical Company, Inc.

[0170] Examples of etching solutions containing any of copper sulfate, iron sulfate, and copper chloride include etching solutions containing copper sulfate, iron sulfate, and copper chloride, with iron sulfate being preferred. Commercially available etching solutions containing any of copper sulfate, iron sulfate, and copper chloride can be used. Examples of commercially available products include "SE-300" manufactured by Meltex and "CupraEtch DE" manufactured by Atotech.

[0171] The temperature when carrying out step (B-3) is preferably 10°C or higher, more preferably 15°C or higher, even more preferably 20°C or higher, and preferably 80°C or lower, more preferably 60°C or lower, even more preferably 50°C or lower.

[0172] The time for carrying out step (B-3) varies depending on the thickness of the metal layer and the type of metal forming the metal layer, but is preferably 0.05 to 60 minutes, more preferably 0.1 to 15 minutes.

[0173] In step (B-4), the photosensitive layer is removed, as shown in FIG. 6 as an example. There are no limitations on the method for removing the photosensitive layer having openings. For example, a photosensitive layer formed of a photoresist composition or a dry film can be removed by contacting it with an appropriate stripping solution depending on the composition of the photosensitive layer. In one example, the photosensitive layer can be removed using an alkaline stripping solution such as a sodium hydroxide solution.

[0174] In another embodiment of step (B), (Ba) forming a metal seed layer on the thermoplastic resin layer; (Bb) forming a post portion on the metal seed layer; (Bc) forming an electroplated layer on the metal seed layer; (Bd) removing the post portion; and (Be) Etching the metal seed layer to form a metal mask pattern.

[0175] In step (Ba), a thin metal seed layer 60 is formed on the thermoplastic resin layer 30, as shown in an example in Fig. 9. Methods for forming the metal seed layer include electroless plating and sputtering. The method for forming the metal seed layer by electroless plating is the same as the method for forming the plating seed layer when forming a metal layer by a semi-additive method.

[0176] When forming a metal seed layer by sputtering, a seed layer is usually first formed on the surface of a thermoplastic resin layer by sputtering, and then a sputtered layer is formed on the seed layer by sputtering. Before forming the seed layer by sputtering, the surface of the thermoplastic resin layer may be cleaned by reverse sputtering. Various gases can be used for the reverse sputtering, with Ar, O2, and N2 being preferred. When the seed layer is made of Cu or a Cu alloy, Ar or O2 or an Ar / O2 mixed gas is preferred. When the seed layer is made of Ti, Ar or N2 or an Ar / N2 mixed gas is preferred. When the seed layer is made of Cr or a Cr alloy (such as nichrome), Ar or O2 or an Ar / O2 mixed gas is preferred. Sputtering can be performed using various sputtering devices, such as magnetron sputtering and mirror tron ​​sputtering. Metals that form the seed layer include Cr, Ni, Ti, and nichrome. Cr and Ti are particularly preferred. The seed layer is typically formed to a thickness of preferably 5 nm or more, more preferably 10 nm or more, and preferably 1000 nm or less, more preferably 500 nm or less. Examples of metals that form the sputtered layer include Cu, Pt, Au, and Pd. Cu and Ti are particularly preferred. The thickness of the sputtered layer is generally preferably 50 nm or more, more preferably 100 nm or more, and is preferably 3000 nm or less, more preferably 1000 nm or less.

[0177] In step (Bb), as shown in FIG. 10, a metal seed layer 60 is formed, and then a post portion 70 is formed on the metal seed layer 60. The post portion 70 is formed by forming a photosensitive layer on the metal seed layer 60 and patterning it. The diameter of the post portion can be the same as the top diameter of the opening in the photosensitive layer. The method for patterning the photosensitive layer is the same as in step (B-2). After forming the post portion 70, a plasma descum treatment may be performed as needed to remove resin residues and the like remaining on the surface of the metal seed layer 60.

[0178] 11, an electroplated layer 80 is formed by electroplating on the metal seed layer 60 from which the photosensitive layer has been removed, i.e., on the surface of the metal seed layer 60 from which the post portions 70 are not present. The method for forming the electroplated layer 80 can be the same as the method for forming the metal layer that serves as the mask in step (B-1). The electroplated layer 80 preferably contains copper.

[0179] The thickness of the electroplated layer is preferably greater than that of the metal seed layer, and the specific thickness of the electroplated layer is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 3 μm or more, and is 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less.

[0180] In the step (Bd), the post portion is removed, as shown in an example in Fig. 12. The method for removing the post portion is the same as in the step (B-4).

[0181] 13, in the step (Be), the metal seed layer 60 exposed from the openings 71 from which the post portions have been removed is etched to remove the metal seed layer in the openings 71, thereby forming a mask pattern (metal mask pattern) 90 having openings 91. The etching method is the same as the etching in the step (B-3).

[0182] Although the mask pattern formed by step (B) is resistant to the wet blasting treatment, it is cut to some extent by the wet blasting treatment. Therefore, from the viewpoint of preventing the mask pattern from being completely cut and disappearing before the recesses are formed, the thickness of the mask pattern is preferably 0.1 μm or more, more preferably 0.5 μm or more, even more preferably 1 μm or more, 1.5 μm or more, or 2 μm or more, and is preferably 70 μm or less, more preferably 60 μm or less, and even more preferably 50 μm or less.

[0183] The top diameter of the openings in the mask pattern is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 35 μm or less. There is no particular lower limit, but it is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. The top diameter of the openings in the mask pattern is the opening diameter, and refers to the diameter of the opening on the surface opposite to the side in contact with the thermoplastic resin layer. The top diameter can be determined by observing the cross section using an SEM.

[0184] <Process (C)> In step (C), a wet blasting process using abrasive grains is performed to form recesses in the insulating layer. As a detailed embodiment of step (C), as shown in FIGS. 6 and 7, abrasive grains are collided with the thermoplastic resin layer 30 and the insulating layer 20 through the mask pattern 40' formed in step (B) to form via holes 100. The wet blasting process is also called wet sandblasting. Note that although the via holes 100 are formed as recesses in FIG. 7, they may be trenches.

[0185] Wet blasting refers to a process in which a slurry liquid containing water and abrasive grains is sprayed from a nozzle onto the surface of areas not covered by a mask pattern, and the abrasive grains are collided with the thermoplastic resin layer and the insulating layer to cut them. The slurry liquid is usually sprayed from the nozzle using air at a predetermined pressure. By cutting the thermoplastic resin layer and the insulating layer, recesses are formed in the thermoplastic resin layer and the insulating layer. In the present invention, the recesses are formed by wet blasting, and the buoyancy of water is added, which makes it possible to suppress the generation of abrasive grain residue at the bottom of the recesses, compared to dry blasting, in which abrasive grains are directly sprayed.

[0186] From the viewpoint of forming small diameter recesses by wet blasting, the modified Mohs hardness of the abrasive grains used in the wet blasting treatment is preferably 1 or more, more preferably 5 or more, and even more preferably 6 or more, or 7 or more. The upper limit can usually be set to 15 or less. The modified Mohs hardness of the abrasive grains can be measured, for example, using a Mohs hardness tester.

[0187] Examples of abrasive grains include inorganic compounds such as silica, glass, and ceria; metal compounds such as steel, stainless steel, zinc, and copper; ceramics such as garnet, zirconia, silicon carbide, alumina, and boron carbide; and particles containing dry ice as a main component. Among these, from the viewpoint of significantly achieving the desired effects of the present invention, inorganic compounds and ceramics are preferred, and any of alumina, silicon carbide, and silica is preferred, with alumina being more preferred. As for silica, crystalline silica is preferred.

[0188] Commercially available abrasive grains can be used, such as "DAW-03" manufactured by Denka Co., Ltd., "AY2-75" (alumina) manufactured by Nippon Steel Chemical & Material Co., Ltd., "GP#4000", "GP#2000", and "SER-A06" (silicon carbide) manufactured by Shinano Electric Refining Co., Ltd., "IMSIL A-8" (crystalline silica) manufactured by Tatsumori Co., Ltd., "Fuji Random WA" (fused alumina) manufactured by Fuji Manufacturing Co., Ltd., and "Macorundum WA" manufactured by Macor Co., Ltd.

[0189] The average particle size of the abrasive grains is preferably 0.3 μm or more, more preferably 0.5 μm or more, even more preferably 1 μm or more, and preferably 20 μm or less, more preferably 15 μm or less, even more preferably 10 μm or less. By setting the average particle size of the abrasive grains within this range, it is possible to form small-diameter recesses. The average particle size of the abrasive grains can be measured, for example, by observation with a scanning electron microscope, and in detail, this can be done by the method described in JP 2008-41932 A.

[0190] The pressure (processing pressure) for spraying the abrasive grains is preferably 0.05 MPa or more, more preferably 0.1 MPa or more, even more preferably 0.15 MPa or more, and preferably 1 MPa or less, more preferably 0.8 MPa or less, even more preferably 0.5 MPa or less. By setting the processing pressure within this range, the processing time can be shortened. The processing pressure here is the value at the surface of the thermoplastic resin layer.

[0191] After step (C) is completed, the mask pattern is removed. Specifically, the mask pattern is removed by etching or the like, and wiring board 1 such as the example shown in Figure 8 is obtained. The etching is the same as the etching in step (B-3) above.

[0192] Although the method for manufacturing a wiring board of the present invention has been described above in which the recesses are via holes, the method can also be used in the case where the recesses are trenches.

[0193] In the method for manufacturing a wiring board of the present invention, a mask pattern is formed on a thermoplastic resin layer, and then recesses are formed by wet blasting, allowing the slope angle of the recesses to be increased. A larger slope angle of the recesses allows the top diameter of the recesses to be made smaller. In other words, wiring boards with smaller diameter recesses can be efficiently manufactured. The slope angle of the recesses in the insulating layer is preferably 55° or more, more preferably 60° or more, even more preferably 65° or more, 70° or more, or 75° or more. There is no particular upper limit, but it is preferably 90° or less, more preferably 88° or less, and even more preferably 85° or less. The slope angle of the recesses in the insulating layer can be determined by the method described in the examples below.

[0194] The method for manufacturing a wiring board of the present invention can increase the gradient angle of the recessed portion, thereby reducing the top diameter of the thermoplastic resin layer after step (C). The top diameter of the thermoplastic resin layer after step (C) is, for example, preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less. There is no particular lower limit, but it is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. The top diameter of the thermoplastic resin layer refers to the diameter of the opening on the surface that contacts the mask pattern. The top diameter of the thermoplastic resin layer can be determined by the method described in the examples below.

[0195] The method for manufacturing a wiring board of the present invention can increase the slope angle of the recessed portion, thereby reducing the bottom diameter of the insulating layer after step (C). The bottom diameter of the insulating layer after step (C) is, for example, preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less. There is no particular lower limit, but it is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. The bottom diameter of the insulating layer refers to the diameter of the opening on the surface that contacts the substrate and the surface that contacts the substrate. The bottom diameter of the insulating layer can be determined by the method described in the examples below.

[0196] The wiring board manufacturing method of the present invention forms recesses by wet blasting. This suppresses heat generation during recess formation, unlike laser recess formation. Smearing is also suppressed. This reduces the step in the cross-sectional shape. Specifically, as shown in an example in FIG. 8, the step distance d from the edge of the first surface 30a of the thermoplastic resin layer 30 in the recessed via hole 100 to the edge of the laminated surface of the first surface 30a and the insulating layer 20 can be reduced. This improves the reliability of the electrical connection. The step distance d is preferably 1.0 μm or less, more preferably 0.5 μm or less, and even more preferably 0.3 μm or less, or 0 μm. There is no particular lower limit, but it can be 0 μm or more, or 0.001 μm or more. The step distance can be adjusted using the method described in the examples below.

[0197] <Other processes> When manufacturing a wiring board, after step (C), a step (D) of roughening treatment and a step (E) of forming a conductor layer may be further performed. Steps (D) and (E) may be performed according to various methods known to those skilled in the art that are used in the manufacture of printed wiring boards. Furthermore, steps (A) to (E) may be repeated as necessary to form a multilayer wiring board.

[0198] Step (D) is a step of roughening the surface and the recesses of the thermoplastic resin layer. This roughening treatment can be performed using the procedures and conditions of known roughening treatments commonly used in forming insulating layers for printed wiring boards. For example, the roughening treatment can be performed in this order: swelling treatment with a swelling liquid, roughening treatment with an oxidizing agent, and neutralization treatment with a neutralizing liquid. The swelling liquid used in the roughening treatment is not particularly limited, but examples include alkaline solutions and surfactant solutions. Alkaline solutions are preferred, with sodium hydroxide solutions and potassium hydroxide solutions being more preferred. Commercially available swelling liquids include "Swelling Dip Securigans P," "Swelling Dip Securigans SBU," and "Swelling Dip Securigant P" manufactured by Atotech Japan. The swelling treatment with a swelling liquid is not particularly limited, but can be performed by immersing the thermoplastic resin layer, etc., in a swelling liquid at 30°C to 90°C for 1 to 20 minutes. To minimize swelling of resins such as thermoplastic resin layers, the insulating layer is preferably immersed in a swelling solution at 40°C to 80°C for 5 to 15 minutes. The oxidizing agent used in the roughening treatment is not particularly limited, but examples include alkaline permanganate solutions prepared by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. Roughening treatment using an oxidizing agent such as alkaline permanganate solution is preferably performed by immersing the thermoplastic resin layer in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. The concentration of permanganate in the alkaline permanganate solution is preferably 5% to 10% by mass. Commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigance P" manufactured by Atotech Japan. The neutralizing solution used in the roughening treatment is preferably an acidic aqueous solution, and a commercially available product such as "Reduction Solution Securigant P" manufactured by Atotech Japan Co., Ltd. Treatment with a neutralizing solution can be carried out by immersing the surface that has been roughened with an oxidizing agent in the neutralizing solution at 30°C to 80°C for 1 minute to 30 minutes.From the viewpoint of workability, a preferred method is to immerse the object that has been subjected to roughening treatment with an oxidizing agent in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

[0199] Step (E) is a step of forming a conductor layer (circuit conductor layer) on the surface of the thermoplastic resin layer. In this step, a conductor layer is also typically formed in the recesses. Therefore, the conductor layer may also be formed on the surface of the insulating layer exposed in the recesses. The conductor material used for the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductor layer may be a single metal layer or an alloy layer. Examples of alloy layers include layers formed from alloys of two or more metals selected from the above group (e.g., nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys). Among these, from the viewpoints of versatility in forming the conductor layer, cost, ease of patterning, etc., a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy, a copper-nickel alloy, or a copper-titanium alloy is preferred, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy is more preferred, and a single metal layer of copper is even more preferred.

[0200] The conductor layer may be a single layer structure or a multi-layer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are laminated. When the conductor layer has a multi-layer structure, the layer in contact with the cured body is preferably a single metal layer of chromium, zinc, or titanium, or an alloy layer of a nickel-chromium alloy.

[0201] The thickness of the conductor layer depends on the desired design of the wiring board, but is generally 3 μm to 35 μm, and preferably 5 μm to 30 μm.

[0202] In a preferred embodiment of step (E), the conductor layer is formed by sputtering. When forming a conductor layer by sputtering, typically, a conductor seed layer is first formed on the surface of the thermoplastic resin layer by sputtering, and then a conductor sputtered layer is formed on the conductor seed layer by sputtering. Before forming the conductor seed layer by sputtering, the surface of the thermoplastic resin layer may be cleaned by reverse sputtering. Various gases can be used for the reverse sputtering, with Ar, O2, and N2 being preferred. When the seed layer is made of Cu or a Cu alloy, Ar or O2 or an Ar / O2 mixed gas is preferred. When the seed layer is made of Ti, Ar or N2 or an Ar / N2 mixed gas is preferred. When the seed layer is made of Cr or a Cr alloy (such as nichrome), Ar or O2 or an Ar / O2 mixed gas is preferred. Sputtering can be performed using various sputtering devices, such as magnetron sputtering and mirror tron ​​sputtering. Metals that form the conductor seed layer include Cr, Ni, Ti, and nichrome. Cr and Ti are particularly preferred. The thickness of the conductive seed layer is usually preferably 5 nm or more, more preferably 10 nm or more, and is preferably 1000 nm or less, more preferably 500 nm or less. Examples of metals that form the conductive sputtered layer include Cu, Pt, Au, and Pd. Cu is particularly preferred. The thickness of the conductive sputtered layer is usually preferably 50 nm or more, more preferably 100 nm or more, and is preferably 3000 nm or less, more preferably 1000 nm or less.

[0203] After forming a conductor layer by sputtering, a copper plating layer may be further formed on the conductor layer by electrolytic copper plating. The thickness of the copper plating layer is usually preferably 5 μm or more, more preferably 8 μm or more, and is preferably formed to be 75 μm or less, more preferably 35 μm or less. Known methods such as subtractive and semi-additive methods can be used to form the circuit.

[0204] The wiring board manufactured by the above-described manufacturing method includes an insulating layer. Furthermore, the wiring board typically includes a conductor layer, such as a conductor layer of a substrate and a circuit conductor layer, and these conductor layers can form circuit wiring. Examples of such wiring boards include printed wiring boards.

[0205] The wiring board manufactured by the above-described manufacturing method can be bonded to a semiconductor chip to manufacture a semiconductor chip package substrate.

[0206] The bonding conditions for the wiring board and the semiconductor chip can be any conditions that allow conductive connection between the terminal electrodes of the semiconductor chip and the circuit wiring of the wiring board. For example, the conditions used in flip-chip mounting of semiconductor chips can be used. Furthermore, for example, the semiconductor chip and the wiring board can be bonded via an insulating adhesive.

[0207] An example of a bonding method is a method in which a semiconductor chip is pressure-bonded to a wiring board. Pressure-bonding conditions are a pressure-bonding temperature typically in the range of 120°C to 240°C (preferably 130°C to 200°C, more preferably 140°C to 180°C), and a pressure-bonding time typically in the range of 1 second to 60 seconds (preferably 5 seconds to 30 seconds).

[0208] Another example of the bonding method is to bond the semiconductor chip to the wiring board by reflow. The reflow conditions may be in the range of 120°C to 300°C.

[0209] Examples of semiconductor package substrates include fan-in type packages and fan-out type packages.

[0210] [Semiconductor Devices] The semiconductor device of the present invention includes a wiring board, and can be manufactured using a wiring board obtained by the manufacturing method of the present invention.

[0211] Examples of semiconductor devices include various semiconductor devices used in electrical appliances (for example, computers, mobile phones, digital cameras, and televisions) and vehicles (for example, motorcycles, automobiles, trains, ships, and aircraft).

[0212] The semiconductor device of the present invention can be manufactured by mounting a component (semiconductor chip) on a conductive portion of a wiring board. The "conductive portion" refers to a portion of the wiring board that transmits an electrical signal, and the portion may be either on the surface or embedded. The semiconductor chip is not particularly limited as long as it is an electrical circuit element made of semiconductor material.

[0213] The method of mounting a semiconductor chip when manufacturing a semiconductor device is not particularly limited as long as the semiconductor chip functions effectively, but specific examples include wire bonding mounting, flip chip mounting, bumpless buildup layer (BBUL) mounting, anisotropic conductive film (ACF) mounting, non-conductive film (NCF) mounting, etc. Here, the "bumpless buildup layer (BBUL) mounting method" refers to "a mounting method in which a semiconductor chip is directly embedded in a recess in a wiring board and the semiconductor chip is connected to the wiring on the wiring board." [Example]

[0214] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Furthermore, the operations described below were carried out in an environment of normal temperature and pressure, unless otherwise specified.

[0215] <Inorganic filler used> Inorganic filler 1: Spherical silica (Admatechs "SC2500SQ", average particle size 0.63 μm, specific surface area 11.2 m) 2 The surface was treated with 1 part of N-phenyl-3-aminopropyltrimethoxysilane (KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) per 100 parts of the silica gel (100 parts per 100g). ·Inorganic filler 2: Spherical silica (“UFP-30” manufactured by Denka, average particle size 0.078 μm, specific surface area 30.7 m 2 The surface was treated with 2 parts of N-phenyl-3-aminopropyltrimethoxysilane (KBM573, manufactured by Shin-Etsu Chemical Co., Ltd.) per 100 parts of the silica gel (100 parts per 100g).

[0216] <Preparation of Resin Composition 1> 6 parts bixylenol type epoxy resin (Mitsubishi Chemical Corporation "YX4000HK", epoxy equivalent: approx. 185 g / eq.), 5 parts naphthalene type epoxy resin (Nippon Steel Chemical & Material Co., Ltd. "ESN475V", epoxy equivalent: approx. 332 g / eq.), 15 parts bisphenol AF type epoxy resin (Mitsubishi Chemical Corporation "YL7760", epoxy equivalent: approx. 238 g / eq.), 2 parts naphthylene ether type epoxy resin (DIC Corporation "HP6000L", epoxy equivalent: approx. 213 g / eq.), cyclohexane type epoxy resin (Mitsubishi Chemical Corporation "YL7760", epoxy equivalent: approx. 238 g / eq.). Two parts of phenoxy resin ("ZX1658GS" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight approximately 135 g / eq.), two parts of phenoxy resin ("YL7500BH30" manufactured by Mitsubishi Chemical Corporation, 1:1 solution of cyclohexanone:methyl ethyl ketone (MEK) with a solid content of 30% by mass, Mw=44000), and five parts of hydrogenated styrene-based thermoplastic elastomer ("P2000" manufactured by Asahi Kasei Corporation, styrene / ethylene-butylene-butadiene ratio=67 / 33) were dissolved in a mixed solvent of 20 parts solvent naphtha, 10 parts cyclohexanone, and 10 parts toluene by heating and stirring. After cooling to room temperature, 4 parts of a triazine skeleton-containing cresol novolac curing agent (DIC Corporation's "LA-3018-50P," hydroxyl group equivalent of approximately 151 g / eq., 2-methoxypropanol solution with a solids content of 50%), 6 parts of an active ester curing agent (DIC Corporation's "HP-B-8151-62T," active group equivalent of 238 g / eq., toluene solution with a solids content of 62%), 30 parts of inorganic filler 1, and 0.05 parts of an amine curing accelerator (4-dimethylaminopyridine (DMAP)) were mixed and dispersed uniformly using a high-speed rotating mixer. The mixture was then filtered through a cartridge filter (ROKITECHNO Corporation's "SHP020") to prepare Resin Composition 1.

[0217] <Preparation of Resin Composition 2> In the preparation of resin composition 1, the amount of inorganic filler 1 was changed from 30 parts to 60 parts. Resin composition 2 was prepared in the same manner as in the preparation of resin composition 1 except for the above.

[0218] <Preparation of Resin Composition 3> In the preparation of resin composition 1, 30 parts of inorganic filler 1 was changed to 30 parts of inorganic filler 2. Resin composition 3 was prepared in the same manner as in the preparation of resin composition 1 except for the above.

[0219] <Preparation of Resin Composition 4> Resin composition 4 was prepared in the same manner as in the preparation of resin composition 1, except that inorganic filler 1 was not used.

[0220] [Table 1] *1: The content when the resin component in the resin composition is 100% by mass *2: The content when the non-volatile components in the resin composition are 100% by mass

[0221] Details of each component listed in the table are as follows: YX4000HK: Bixylenol epoxy resin, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight approximately 185g / eq. ESN475V: Naphthalene-type epoxy resin, manufactured by Nippon Steel Chemical & Material Co., Ltd., epoxy equivalent weight approximately 332g / eq. YL7760: Bisphenol AF epoxy resin, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight approximately 238g / eq. HP6000L: Naphthylene ether epoxy resin, manufactured by DIC Corporation, epoxy equivalent weight approximately 213g / eq. ZX1658GS: Cyclohexane-type epoxy resin, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight approximately 135g / eq. LA-3018-50P: Triazine skeleton-containing cresol novolac curing agent, manufactured by DIC Corporation, hydroxyl equivalent weight approximately 151g / eq., 50% solids solution in 2-methoxypropanol HPB-8151-62T: DIC Corporation, active group equivalent weight 238g / eq., toluene solution with 62% solids YX7500BH30: Phenoxy resin, manufactured by Mitsubishi Chemical Corporation, 1:1 solution of cyclohexanone and methyl ethyl ketone (MEK) with a solid content of 30% by mass, Mw=44,000 P2000: Hydrogenated styrene-based thermoplastic elastomer, manufactured by Asahi Kasei Corporation (styrene / ethylene-butylene-butadiene ratio = 67 / 33) DMAP: Amine curing accelerator, 4-dimethylaminopyridine

[0222] <Measurement of tensile modulus of cured resin composition layer (insulating layer)> A PET film ("Lumirror R80" manufactured by Toray Industries, Inc., thickness 38 μm, softening point 130°C, "release PET") that had been release-treated with an alkyd resin-based release agent ("AL-5" manufactured by Lintec Corporation) was prepared as a support. Resin compositions 1 to 4 were each uniformly applied to the release agent on the support using a die coater so that the thickness of the resin composition layer after drying would be 40 μm. The film was then dried at 70°C to 95°C for 3 minutes to form a resin composition layer on the release PET, thereby obtaining a resin sheet. The resin sheet was cut into a 167 × 107 mm square.

[0223] A release PET film ("501010" manufactured by Lintec Corporation, 38 μm thick, 240 mm square) was placed on a glass cloth-based epoxy resin double-sided copper-clad laminate ("R-1515A" manufactured by Panasonic Corporation, 0.8 mm thick, 255 mm square) so that the untreated surface of the release PET film was in contact with the glass cloth-based epoxy resin double-sided copper-clad laminate, and the four sides of the release PET film were fixed with polyimide adhesive tape (10 mm wide).

[0224] The resin sheet was centrally laminated using a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd., two-stage build-up laminator, CVP700) so that the resin composition layer was in contact with the release surface of a release PET film (Lintec Corporation, "501010," 38 μm thick, 240 mm square). The lamination was performed by reducing the pressure to 13 hPa or less for 30 seconds, and then pressing the film at 100°C and a pressure of 0.74 MPa for 30 seconds.

[0225] The release PET was peeled off, and the resin composition layer was cured at 180°C for 90 minutes to obtain a cured product for evaluation. The cured product for evaluation was cut into a dumbbell-shaped No. 1 test piece to obtain a test piece. The tensile strength of this test piece was measured using a tensile tester ("RTC-1250A" manufactured by Orientec Co., Ltd.), and the modulus of elasticity at 23°C was determined. The measurement was performed in accordance with JIS K7127. This operation was performed three times, and the average value was calculated.

[0226] Example 1 -Making resin sheets- As a support, a PET film ("Lumirror R80" manufactured by Toray Industries, Inc., thickness 38 μm, softening point 130°C, "Release PET") that had been release-treated with an alkyd resin-based release agent ("AL-5" manufactured by Lintec Corporation) was prepared. Resin composition 1 was uniformly applied to the release agent on the support using a die coater so that the thickness of the resin composition layer after drying would be 10 μm, and the resulting film was dried at 70°C to 95°C for 3 minutes to obtain a resin composition layer on the support. Next, a rough surface of a polypropylene film ("Alphan MA-411" manufactured by Oji F-Tex Co., Ltd., thickness 15 μm) was laminated as a protective film on the side of the resin composition layer that was not bonded to the support, so as to be bonded to the resin composition layer. This resulted in a resin sheet consisting of the support, resin composition layer, and protective film in that order.

[0227] -Preparation of resin sheet for forming thermoplastic resin layer- As a resin sheet for forming a thermoplastic resin layer, Upilex S (polyimide, manufactured by UBE Corporation, thickness 12.5 μm) was prepared.

[0228] -Creating a test board- (Process (A)) A silicon wafer with a thermally oxidized surface and a sputtered seed layer (Ti / Cu = 50 nm / 3000 nm) was prepared. The surface of this wafer was roughened using a microetching agent (MEC Corporation's "CZ8201") (copper etching amount: 0.5 μm, arithmetic mean roughness after roughening (Ra): 310 nm) to obtain a substrate.

[0229] The arithmetic mean roughness (Ra) of the substrate surface after roughening treatment was measured using a non-contact surface roughness meter (WYKO NT3300, manufactured by Veeco Instruments). The arithmetic mean roughness (Ra) was measured in accordance with ISO 25178.

[0230] The resin sheet, from which the protective film had been removed, was laminated onto the substrate using a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd., single-stage build-up laminator, V160) so that the resin composition layer was in contact with the substrate. Lamination was performed by reducing the pressure to 30 hPa or less for 30 seconds, and then pressing the sheet at 100°C and 0.3 MPa for 30 seconds.

[0231] Next, the PET film of the resin sheet for forming a thermoplastic resin layer was peeled off, and a thermoplastic resin layer was laminated onto the resin composition layer under the same conditions as those for laminating the resin composition layer.

[0232] After laminating the thermoplastic resin layer onto the resin composition layer, the resin composition layer was cured by heating at 130°C for 30 minutes and then at 170°C for 30 minutes to form an insulating layer.

[0233] (Process (B)) A metal seed layer was obtained by sputtering on the thermoplastic resin layer using a sputtering device (Canon Anelva's "E-400S") to form a 30 nm thick titanium layer and then a 200 nm thick copper layer.

[0234] A positive liquid resist (Tokyo Ohka Kogyo Co., Ltd., P-CM75) was spin-coated onto the metal seed layer at 1500 rpm for 30 seconds. The resulting positive liquid resist was then heated at 120°C for 180 seconds to form a 7 μm thick film. The resist was then exposed to light using an I-line stepper (Nikon Corporation, NSR-2005i9C) for 115 msec at a focus of -1.5 μm. The resist was then post-baked at 100°C for 90 seconds and developed in a 2.38% tetramethylammonium hydroxide (TMAH) solution for 90 seconds to form 30 μm diameter posts.

[0235] After forming the post portion, a descum treatment was performed using a plasma device (manufactured by Yamato Chemical Co., Ltd., product name PM100; O2 flow rate 50 sccm, RF power: 200 W, process pressure: 10 Pa, treatment time: 2 minutes) to remove residue remaining on the surface of the metal seed layer.

[0236] Electrolytic copper plating was performed at 0.132 A for 65 minutes to form a 6 μm thick electroplated metal layer. The posts were stripped using a stripper (Mitsubishi Gas Chemical Company, Inc., ST-120). The sputter-plated copper layer was etched using 500 mL of Mitsubishi Gas Chemical Company, Inc.'s "WLC-C2" solution and 500 mL of pure water at room temperature for 25 seconds. The titanium layer was etched using 200 mL of Meltex Corporation's "Ti-3991" solution, 400 mL of 35% HO2, and 400 mL of pure water at room temperature for 120 seconds to form a copper mask pattern with 6 μm thick, 30 μm diameter holes. The sample after step (B) is hereinafter referred to as Sample A.

[0237] (Process (C)) Sample A was subjected to wet blasting to form via holes. Alumina abrasive grains (Macorundum WA#2000, manufactured by Macor Corporation, average particle size 6.7 μm) were dispersed in water to a concentration of 10 mass % to prepare a slurry. The slurry was sprayed onto Sample A together with compressed air at an air pressure of 0.25 MPa, and wet blasting was performed until the copper on the substrate was exposed, yielding a test substrate.

[0238] <Evaluation of via hole formation> The test substrate was visually inspected and evaluated according to the following criteria. O: Copper mask pattern remains. ×: The copper mask pattern has disappeared.

[0239] <Checking the step distance of the via hole> After the wet blasting treatment, the surface of the test substrate was washed with high-pressure water, then immersed in 5% diluted sulfuric acid at 25°C for 1 minute, washed again with water, and dried. Thereafter, the cross section of the step at the interface between the thermoplastic resin layer and the insulating layer of the test substrate was observed using a FIBSEM (Hitachi High-Tech Science Corporation, "ETHOS NX5000") and evaluated according to the following criteria. ○: The step distance at the interface is less than 0.5 μm ×: Step distance at interface is 0.5 μm or more

[0240] <Checking for abrasive residue at the bottom of the via hole> After the wet blasting treatment, the surface of the test substrate was washed with high-pressure water, then immersed in 5% diluted sulfuric acid at 25°C for 1 minute, washed with water again, and dried. Thereafter, the cross section of the via hole of the test substrate was observed using a FIBSEM (Hitachi High-Tech Science Corporation, "ETHOS NX5000") and evaluated according to the following criteria. 〇: No abrasive grain residue is visible ×: Abrasive grain residue is observed

[0241] <Measurement of top diameter, via diameter, and via hole gradient angle> After wet blasting, the cross-sectional shape of the via holes in the test substrate was observed using a FIBSEM (Hitachi High-Tech Science Corporation, "ETHOS NX5000"), and the via diameter, top diameter, and slope angle of the via holes were measured.

[0242] <Example 2> In Example 1, Resin Composition 1 was changed to Resin Composition 2. Except for the above, the via hole formability and the like were evaluated in the same manner as in Example 1.

[0243] Example 3 In Example 1, Resin Composition 1 was changed to Resin Composition 3. Except for the above, the via hole formability and the like were evaluated in the same manner as in Example 1.

[0244] Example 4 In Example 1, Resin Composition 1 was changed to Resin Composition 4. Except for the above, the via hole formability and the like were evaluated in the same manner as in Example 1.

[0245] <Example 5> In Example 1, the substrate having an arithmetic mean roughness (Ra) of 310 nm after the roughening treatment was changed to a substrate having an arithmetic mean roughness (Ra) of 570 nm after the roughening treatment. Except for the above, the via hole formability and the like were evaluated in the same manner as in Example 1.

[0246] <Comparative Example 1> In Example 1, step (B) was not performed, and step (C) was changed to the following step: Via hole formability and the like were evaluated in the same manner as in Example 1 except for the above points.

[0247] A via hole was formed using a UV laser on the thermoplastic resin layer of Sample A. The UV laser was irradiated using a UV laser processing machine (manufactured by Via Mechanics, "LU-2L212 / M50L") under the conditions of 35 shots and 0.08 W power.

[0248] After laser processing, the specimen was subjected to the following desmearing process. The specimen was immersed in a swelling solution, Swelling Dip Securigant P (manufactured by Atotech Japan) containing diethylene glycol monobutyl ether, at 60°C for 5 minutes. Next, the specimen was immersed in a roughening solution, Concentrate Compact P (manufactured by Atotech Japan) (aqueous solution of 60 g / L KMnO4 and 40 g / L NaOH), at 80°C for 15 minutes. Finally, the specimen was immersed in a neutralizing solution, Reduction Showreusin Securigant P (manufactured by Atotech Japan) for 5 minutes at 40°C.

[0249] <Comparative Example 2> In Example 5, steps (B) and (C) were changed to the following steps: Except for the above, the via hole formability and the like were evaluated in the same manner as in Example 5.

[0250] A 20 μm-thick dry film (Nikko Materials Co., Ltd., "ALPHO 20A263") was laminated on the thermoplastic resin layer. The dry film was laminated using a batch-type vacuum pressure laminator (Meiki Seisakusho Co., Ltd., "MVLP-500"), which was depressurized for 30 seconds to a pressure of 13 hPa or less, and then pressurized at a pressure of 0.1 MPa and a temperature of 70°C for 20 seconds. A glass mask with a via pattern was then placed on the polyethylene terephthalate film, which was the protective layer for the dry film, and a UV lamp was used to irradiate the film at an irradiation intensity of 150 mJ / cm. 2 After UV irradiation, the film was sprayed with a 1% aqueous sodium carbonate solution at 30°C for 30 seconds at a spray pressure of 0.15 MPa. After that, the film was washed with water and patterned to form via holes with a top diameter of 30 μm, obtaining a dry film mask pattern.

[0251] Using alumina (average particle size 6.7 μm, Macorundum WA#2000 manufactured by Macor) as abrasive grains, dry blasting was performed on the insulating layer and thermoplastic resin layer that were not covered by the dry film mask pattern at a processing pressure of 0.2 MPa to form via holes.

[0252] [Table 2]

[0253] In Examples 1 to 5, a mask pattern was formed on a thermoplastic resin layer, and then the via holes were formed by wet blasting, which resulted in excellent via hole formation (recess formation) and a small step distance. Furthermore, the via hole had a large slope, which allowed the diameter of the recess to be small.

[0254] On the other hand, in Comparative Example 1, the via holes are formed using a UV laser instead of wet blasting, but it is clear that the step distance is larger than in Examples. Also, in Comparative Example 2, the via holes are formed by dry blasting instead of wet blasting, but it is clear that the formability of the via holes (formability of the recesses) is inferior compared to Examples. [Explanation of symbols]

[0255] 1 Wiring board 10 Base material 20a Resin composition layer 20 insulating layer 30 Thermoplastic resin layer 30a 1st page 30b 2nd side 40 metal layer 40' Mask Pattern 41 Opening 50 Photosensitive layer 51 Opening 60 Metal seed layer 70 Post Department 71 Opening 80 electroplated layer 90 Mask Patterns 91 Opening 100 Beer Hall d Step distance θ is the angle between the bottom of the via hole and the wall of the via hole

Claims

1. (A) forming an insulating layer containing a cured product of a resin composition and a thermoplastic resin layer in this order on a substrate; (B) forming a mask pattern on the thermoplastic resin layer; and (C) A method for manufacturing a wiring board, comprising a step of performing a wet blasting process using abrasive grains to form recesses in the thermoplastic resin layer and the insulating layer.

2. The method for producing a wiring board according to claim 1 , wherein the resin composition comprises a thermosetting resin.

3. The method for manufacturing a wiring board according to claim 2 , wherein the thermosetting resin includes an epoxy resin.

4. The method for manufacturing a wiring board according to claim 2 , wherein the thermosetting resin contains a curing agent.

5. The method for producing a wiring board according to claim 4 , wherein the curing agent includes an active ester curing agent.

6. The method for producing a wiring board according to claim 1 , wherein the resin composition contains an inorganic filler.

7. The method for producing a wiring board according to claim 6 , wherein the inorganic filler comprises silica or alumina.

8. The method for producing a wiring board according to claim 6 , wherein the content of the inorganic filler is 20% by mass or more when the non-volatile components of the resin composition are taken as 100% by mass.

9. The method for producing a wiring board according to claim 1 , wherein the thermoplastic resin layer contains polyimide.

10. 2. The method for producing a wiring board according to claim 1, wherein b / c is 0.5 or more and 10 or less, where b is the thickness of the thermoplastic resin layer and c is the thickness of the insulating layer.

11. The method for manufacturing a wiring board according to claim 1 , wherein the insulating layer has a tensile modulus of elasticity of 1 GPa or more.

12. 2. The method for manufacturing a wiring board according to claim 1, wherein the mask pattern has a thickness of 1 [mu]m or more.

13. The method for manufacturing a wiring board according to claim 1 , wherein the mask pattern is a metal mask pattern.

14. The method for manufacturing a wiring board according to claim 13 , wherein the metal mask pattern comprises copper.

15. The method for manufacturing a wiring board according to claim 1 , wherein the wiring board is a semiconductor package substrate.

16. 2. The method for manufacturing a wiring board according to claim 1, wherein the wiring board is used in a semiconductor device.

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